x86/boot: Use __ALIGN_KERNEL_MASK() instead of open coded analogue

x86/boot: Use __ALIGN_KERNEL_MASK() instead of open coded analogue

LOAD_PHYSICAL_ADDR is calculated as an aligned (up) CONFIG_PHYSICAL_START
with the respective alignment value CONFIG_PHYSICAL_ALIGN. However,
the code is written openly while we have __ALIGN_KERNEL_MASK() macro
that does the same. This macro has nothing special, that's why
it may be used in assembler code or linker scripts (on the contrary
__ALIGN_KERNEL() may not). Do it so.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20250404165303.3657139-1-andriy.shevchenko@linux.intel.com