intel: Drop SURFACE_FORMAT enum from genxml.

intel: Drop SURFACE_FORMAT enum from genxml.

We want people to be using ISL_FORMAT_*, rather than the genxml format
enumerations. This patch drops 10 separate copies, and drops a bunch
of ugly casting.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
[jordan.l.justen@intel.com: Minor changes for rebase]
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>