accel: Add .mmap to DRM_ACCEL_FOPS

In reviewing the ivpu driver, DEFINE_DRM_ACCEL_FOPS could have been used
if DRM_ACCEL_FOPS defined .mmap to be drm_gem_mmap. Lets add that since
accel drivers are a variant of drm drivers, modern drm drivers are
expected to use GEM, and mmap() is a common operation that is expected
to be heavily used in accel drivers thus the common accel driver should
be able to just use DEFINE_DRM_ACCEL_FOPS() for convenience.

Signed-off-by: Jeffrey Hugo <[e-mail]>
Reviewed-by: Oded Gabbay <[e-mail]>
Signed-off-by: Oded Gabbay <[e-mail]>

include/drm/drm_accel.h

···
 	.compat_ioctl	= drm_compat_ioctl,\
 	.poll		= drm_poll,\
 	.read		= drm_read,\
-	.llseek		= noop_llseek
+	.llseek		= noop_llseek, \
+	.mmap		= drm_gem_mmap
 
 /**
  * DEFINE_DRM_ACCEL_FOPS() - macro to generate file operations for accelerators drivers