x86/PV: consistently inline {,un}adjust_guest_l<N>e()

x86/PV: consistently inline {,un}adjust_guest_l<N>e()

Commit 8a74707a7c ("x86/nospec: Use always_inline to fix code gen for
evaluate_nospec") converted inline to always_inline for
adjust_guest_l[134]e(), but left adjust_guest_l2e() and
unadjust_guest_l3e() alone without saying why these two would differ in
the needed / wanted treatment. Adjust these two as well.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>