intel/fs: Exclude control sources from execution type and region alignment calculations.

Currently the execution type calculation will return a bogus value in
cases like:

  mov_indirect(8) vgrf0:w, vgrf1:w, vgrf2:ud, 32u

Which will be considered to have a 32-bit integer execution type even
though the actual indirect move operation will be carried out with
16-bit precision.

Similarly there's no need to apply the CHV/BXT double-precision region
alignment restrictions to such control sources, since they aren't
directly involved in the double-precision arithmetic operations
emitted by these virtual instructions.  Applying the CHV/BXT
restrictions to control sources was expected to be harmless if mildly
inefficient, but unfortunately it exposed problems at codegen level
for virtual instructions (namely the SHUFFLE instruction used for the
Vulkan 1.1 subgroup feature) that weren't prepared to accept control
sources with an arbitrary strided region.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109328


Reported-by: Mark Janes <mark.a.janes@intel.com>
Fixes: efa4e4bc "intel/fs: Introduce regioning lowering pass."
Tested-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
(cherry picked from commit c3c27762)