x86: Fix register pretty print
x86: Fix register pretty print

We're following the AT&T syntax so use a "%" prefix for register names.

Signed-off-by: Pekka Enberg <add4fcd06328a394f0ad91feda7ee057316dc5ed@cs.helsinki.fi>

monocasa/libcpu,curtiszimmerman/libcpu,monocasa/libcpu,glguida/libcpu,libcpu/libcpu,ukatemi/libcpu,ukatemi/libcpu,curtiszimmerman/libcpu,glguida/libcpu,libcpu/libcpu,monocasa/libcpu,monocasa/libcpu,libcpu/libcpu,glguida/libcpu,libcpu/libcpu,curtiszimmerman/libcpu,ukatemi/libcpu,ukatemi/libcpu,curtiszimmerman/libcpu,glguida/libcpu