drm/msm/adreno: set cx_misc_mmio regardless of if platform has LLCC

drm/msm/adreno: set cx_misc_mmio regardless of if platform has LLCC

Platforms without a LLCC (e.g. milos) still need to be able to read and
write to the cx_mem region. Previously if LLCC slices were unavailable
the cx_misc_mmio mapping was overwritten with ERR_PTR, causing a crash
when the GMU later accessed cx_mem.

Move the cx_misc_mmio mapping out of a6xx_llc_slices_init() into
a6xx_gpu_init() so that cx_mem mapping is independent of LLCC.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Signed-off-by: Alexander Koskovich <akoskovich@pm.me>
Patchwork: https://patchwork.freedesktop.org/patch/728808/
Message-ID: <20260528-adreno-810-v7-4-7fe7fdd97fc2@pm.me>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>