x86/asm-offsets: Export certain 'struct cpuinfo_x86' fields for 64-bit asm use too

Expose certain 'struct cpuinfo_x86' fields via asm-offsets for x86_64
too, so that it will be possible to set CPU capabilities from 64-bit
asm code.

32-bit already used these fields, so simply move those offset exports into
the unified asm-offsets.c file.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250514104242.1275040-12-ardb+git@google.com