drm: renesas: rz-du: Fix redefinition errors related to rzg2l_du_vsp_*()

CONFIG_DRM_RCAR_VSP is related to R-Car and not related to RZ/G2L
specific. This caused the below build issue. Fix this errors by replacing
CONFIG_DRM_RCAR_VSP->CONFIG_VIDEO_RENESAS_VSP1. While at it, use
IS_ENABLED() macro.

drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:47:6: error: redefinition of 'rzg2l_du_vsp_enable'
47 | void rzg2l_du_vsp_enable(struct rzg2l_du_crtc *crtc)
| ^~~~~~~~~~~~~~~~~~~
In file included from drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h:18,
from drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:30:
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h:72:20: note: previous definition of 'rzg2l_du_vsp_enable' with type 'void(struct rzg2l_du_crtc *)'
72 | static inline void rzg2l_du_vsp_enable(struct rzg2l_du_crtc *crtc) { };
| ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:61:6: error: redefinition of 'rzg2l_du_vsp_disable'
61 | void rzg2l_du_vsp_disable(struct rzg2l_du_crtc *crtc)
| ^~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h:73:20: note: previous definition of 'rzg2l_du_vsp_disable' with type 'void(struct rzg2l_du_crtc *)'
73 | static inline void rzg2l_du_vsp_disable(struct rzg2l_du_crtc *crtc) { };
| ^~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:66:6: error: redefinition of 'rzg2l_du_vsp_atomic_flush'
66 | void rzg2l_du_vsp_atomic_flush(struct rzg2l_du_crtc *crtc)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h:74:20: note: previous definition of 'rzg2l_du_vsp_atomic_flush' with type 'void(struct rzg2l_du_crtc *)'
74 | static inline void rzg2l_du_vsp_atomic_flush(struct rzg2l_du_crtc *crtc) { };
| ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:76:19: error: redefinition of 'rzg2l_du_vsp_get_drm_plane'
76 | struct drm_plane *rzg2l_du_vsp_get_drm_plane(struct rzg2l_du_crtc *crtc,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h:75:33: note: previous definition of 'rzg2l_du_vsp_get_drm_plane' with type 'struct drm_plane *(struct rzg2l_du_crtc *, unsigned int)'
75 | static inline struct drm_plane *rzg2l_du_vsp_get_drm_plane(struct rzg2l_du_crtc *crtc,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.c:302:5: error: redefinition of 'rzg2l_du_vsp_init'
302 | int rzg2l_du_vsp_init(struct rzg2l_du_vsp *vsp, struct device_node *np,
| ^~~~~~~~~~~~~~~~~
drivers/gpu/drm/renesas/rz-du/rzg2l_du_vsp.h:66:19: note: previous definition of 'rzg2l_du_vsp_init' with type 'int(struct rzg2l_du_vsp *, struct device_node *, unsigned int)'
66 | static inline int rzg2l_du_vsp_init(struct rzg2l_du_vsp *vsp, struct device_node *np,
| ^~~~~~~~~~~~~~~~~

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20240222124610.383e1ce3@canb.auug.org.au/T/#u
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 768e9e61b3b9 ("drm: renesas: Add RZ/G2L DU Support")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240222112643.110326-1-biju.das.jz@bp.renesas.com

drm: renesas: Add RZ/G2L DU Support

The LCD controller is composed of Frame Compression Processor (FCPVD),
Video Signal Processor (VSPD), and Display Unit (DU).

It has DPI/DSI interfaces and supports a maximum resolution of 1080p
along with 2 RPFs to support the blending of two picture layers and
raster operations (ROPs).

The DU module is connected to VSPD. Add RZ/G2L DU support for RZ/G2L
alike SoCs.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20240218164840.57662-4-biju.das.jz@bp.renesas.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>