drm/amd/ras: Fix NULL deref in ras_core_ras_interrupt_detected()

drm/amd/ras: Fix NULL deref in ras_core_ras_interrupt_detected()

Fixes a NULL pointer dereference when ras_core is NULL and ras_core->dev
is accessed in the error path.

Fixes: 13c91b5b4378 ("drm/amd/ras: Add rascore unified interface function")
Reported by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: YiPeng Chai <YiPeng.Chai@amd.com>
Cc: Tao Zhou <tao.zhou1@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>