powerpc/xmon: Remove unused #defines
powerpc/xmon: Remove unused #defines

Neither REGS_PER_LINE or LAST_VOLATILE are used, nor have they ever
been as far back as I can see.

Signed-off-by: Michael Ellerman <17b9e1c64588c7fa6419b4d29dc1f4426279ba01@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs