x86/mm: Use static inlines for {,un}adjust_guest_l?e()

x86/mm: Use static inlines for {,un}adjust_guest_l?e()

There is no need for these to be macros, and the result is easier to read.

No functional change, but bloat-o-meter reports the following improvement:

  add/remove: 1/0 grow/shrink: 2/3 up/down: 235/-427 (-192)
  function                                     old     new   delta
  __get_page_type                             5231    5351    +120
  adjust_guest_l1e.isra                          -      96     +96
  free_page_type                              1540    1559     +19
  ptwr_emulated_update                        1008     957     -51
  create_grant_pv_mapping                     1342    1186    -156
  mod_l1_entry                                1892    1672    -220

adjust_guest_l1e(), now being a compiler-visible single unit, is chosen for
out-of-line'ing from its several callsites.  The other helpers remain inline.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>