x86: Get rid of some unnecessary TheISA-es in x86.

The X86ISA namespace is already available.

Change-Id: I5774968fdfb30b01eba52cdec5e6ef2c75cb66e4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18471
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed