intel/blorp: Handle bit-casting UNORM and BGRA formats

intel/blorp: Handle bit-casting UNORM and BGRA formats

In f132e0fddfa, I attempted to allow BLORP to do CCS_E copies by using
the UNORM formats instead.  However, the old BLORP bit-cast code could
only handle RGBA formats and asserted on anything other than UINT
formats.  The reason we didn't catch this is because it only comes up on
Gen12 platforms which aren't in our normal CI yet.

Fixes: f132e0fddfad "intel/blorp: Add support for CCS_E copies with..."
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3593>