drm/amdgpu: Fix uninitalized variable in jpeg_v4_0_3_is_idle & jpeg_v4_0_3_wait_for_idle

drm/amdgpu: Fix uninitalized variable in jpeg_v4_0_3_is_idle & jpeg_v4_0_3_wait_for_idle

drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c:752:4: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
                        ret &= ((RREG32_SOC15_OFFSET(
                        ^~~
drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c:745:10: note: initialize the variable 'ret' to silence this warning
        bool ret;
                ^
                 = 0
drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c:774:4: error: variable 'ret' is uninitialized when used here [-Werror,-Wuninitialized]
                        ret &= SOC15_WAIT_ON_RREG_OFFSET(
                        ^~~
drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c:767:9: note: initialize the variable 'ret' to silence this warning
        int ret;
               ^
                = 0
2 errors generated.

Cc: Luben Tuikov <luben.tuikov@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: James Zhu <James.Zhu@amd.com>
Cc: Leo Liu <leo.liu@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>