drm/amd/pm: avoid unaligned access warnings

When building on OpenBSD/arm64 with clang 15, unaligned access
warnings are seen when a union is embedded inside a packed struct.

drm/amd/pm/powerplay/hwmgr/vega20_pptable.h:136:17: error: field
smcPPTable within 'struct _ATOM_VEGA20_POWERPLAYTABLE' is less aligned
than 'PPTable_t' and is usually due to
'struct _ATOM_VEGA20_POWERPLAYTABLE' being packed, which can lead to
unaligned accesses [-Werror,-Wunaligned-access]
PPTable_t smcPPTable;
^

Make PPTable_t packed to avoid this.

Signed-off-by: Jonathan Gray <jsg@jsg.id.au>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/pm: relocate the power related headers

Instead of centralizing all headers in the same folder. Separate them into
different folders and place them among those source files those who really
need them.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>