drm/radeon/kms: Fix RS600/RV515/R520/RS690 IRQ

Bad generated header file leaded to use wrong register
to check IRQ status and acknowledge them. Fix the header
and use proper registers.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>