x86/mm: Use PAGE_ALIGNED(x) instead of IS_ALIGNED(x, PAGE_SIZE)

The <linux/mm.h> already provides the PAGE_ALIGNED() macro. Let's
use this macro instead of IS_ALIGNED() and passing PAGE_SIZE directly.

No change in functionality.

[ mingo: Tweak changelog. ]

Signed-off-by: Fanjun Kong <bh1scw@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220526142038.1582839-1-bh1scw@gmail.com