x86/mm: Remove duplicate definition of _PAGE_PAT_LARGE

_PAGE_PAT_LARGE is already defined next to _PAGE_PAT. Remove the
duplicate.

Fixes: 4efb5664 ("x86/mm: Tabulate the page table encoding definitions")
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20201111160946.147341-2-nivedita@alum.mit.edu