drm/radeon: Make sure radeon_vm_bo_set_addr always unreserves the BO

drm/radeon: Make sure radeon_vm_bo_set_addr always unreserves the BO

commit ee18e599251ed06bf0c8ade7c434a0de311342ca upstream.

Some error paths didn't unreserve the BO. This resulted in a deadlock
down the road on the next attempt to reserve the (still reserved) BO.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90873
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>