x86: Misc trivial cleanup of bootsym_phys()

x86: Misc trivial cleanup of bootsym_phys()

In smpboot, there is no need to abstract setup_trampoline() away.  Drop the
define and use bootsym_phys() directly.

In tboot, the 3 size calculations are invariant of their bootsym_phys()/__pa()
transformations, but the compiler can't tell this.  Drop the tranformations,
which simplifies the compiled function.

  add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-134 (-134)
  Function                                     old     new   delta
  tboot_shutdown                               620     486    -134
  Total: Before=3337042, After=3336908, chg -0.00%

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