um: Include missing headers in asm/pgtable.h

um: Include missing headers in asm/pgtable.h

Formerly, asm/pgtable.h relied on the implicit inclusion of asm/page.h
and linux/mm_types.h via asm/fixmap.h. With the removal of asm/fixmap.h,
these headers need to be included explicitly in asm/pgtable.h now.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501131814.E6CxjulL-lkp@intel.com/
Fixes: 5bfc4a3a0af3 ("um: Remove obsolete fixmap support")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20250113153218.3331321-2-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>