drm/amdgpu: Add helper funcs for jpeg devcoredump

drm/amdgpu: Add helper funcs for jpeg devcoredump

Add devcoredump helper functions that can be reused for all jpeg versions.

V2: (Lijo)
 - add amdgpu_jpeg_reg_dump_init() and amdgpu_jpeg_reg_dump_fini()
 - use reg_list and reg_count from init() to dump and print registers
 - memory allocation and freeing is moved to the init() and fini()

V3: (Lijo)
 - move amdgpu_jpeg_reg_dump_fini() to sw_fini()

Signed-off-by: Sathishkumar S <sathishkumar.sundararaju@amd.com>
Acked-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>