x86/mm: Drop unneeded __always_inline for p4d page table helpers

This reverts the following commits:

  1ea66554 ("x86/mm: Mark p4d_offset() __always_inline")
  046c0dbe ("x86: Mark native_set_p4d() as __always_inline")

p4d_offset(), native_set_p4d() and native_p4d_clear() were marked
__always_inline in attempt to move __pgtable_l5_enabled into __initdata
section.

It was required as KASAN initialization code is a user of
USE_EARLY_PGTABLE_L5, so all pgtable_l5_enabled() translated to
__pgtable_l5_enabled there. This includes pgtable_l5_enabled() called
from inline p4d helpers.

If compiler would decided to not inline these p4d helpers, but leave
them standalone, we end up with section mismatch.

We don't need __always_inline here anymore. __pgtable_l5_enabled moved
back to be __ro_after_init. See the following commit:

  51be1335 ("Revert "x86/mm: Mark __pgtable_l5_enabled __initdata"")

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180626100341.49910-1-kirill.shutemov@linux.intel.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>