drm/panthor: Fix error code in panthor_gpu_init()

This code accidentally returns zero/success on error because of a typo.
It should be "irq" instead of "ret". The other thing is that if
platform_get_irq_byname() were to return zero then the error code would
be cmplicated. Fortunately, it does not so we can just change <= to
< 0.

Fixes: 5cd894e258c4 ("drm/panthor: Add the GPU logical block")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d753e684-43ee-45c2-a1fd-86222da204e1@moroto.mountain

drm/panthor: Fix spelling mistake "readyness" -> "readiness"

There is a spelling mistake in a drm_err message. Fix it.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240326100219.43989-1-colin.i.king@gmail.com

drm/panthor: Add the GPU logical block

Handles everything that's not related to the FW, the MMU or the
scheduler. This is the block dealing with the GPU property retrieval,
the GPU block power on/off logic, and some global operations, like
global cache flushing.

v6:
- Add Maxime's and Heiko's acks

v5:
- Fix GPU_MODEL() kernel doc
- Fix test in panthor_gpu_block_power_off()
- Add Steve's R-b

v4:
- Expose CORE_FEATURES through DEV_QUERY

v3:
- Add acks for the MIT/GPL2 relicensing
- Use macros to extract GPU ID info
- Make sure we reset clear pending_reqs bits when wait_event_timeout()
times out but the corresponding bit is cleared in GPU_INT_RAWSTAT
(can happen if the IRQ is masked or HW takes to long to call the IRQ
handler)
- GPU_MODEL now takes separate arch and product majors to be more
readable.
- Drop GPU_IRQ_MCU_STATUS_CHANGED from interrupt mask.
- Handle GPU_IRQ_PROTM_FAULT correctly (don't output registers that are
not updated for protected interrupts).
- Minor code tidy ups

Cc: Alexey Sheplyakov <asheplyakov@basealt.ru> # MIT+GPL2 relicensing
Co-developed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Steven Price <steven.price@arm.com> # MIT+GPL2 relicensing,Arm
Acked-by: Grant Likely <grant.likely@linaro.org> # MIT+GPL2 relicensing,Linaro
Acked-by: Boris Brezillon <boris.brezillon@collabora.com> # MIT+GPL2 relicensing,Collabora
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240229162230.2634044-5-boris.brezillon@collabora.com