[compiler-rt][hwasan] Support for new Intel LAM API

New version of Intel LAM patches
(https://lore.kernel.org/linux-mm/20220712231328.5294-1-kirill.shutemov@linux.intel.com/)
uses a different interface based on arch_prctl():
 - arch_prctl(ARCH_GET_UNTAG_MASK, &mask) returns the current mask for
   untagging the pointers. We use it to detect kernel LAM support.
 - arch_prctl(ARCH_ENABLE_TAGGED_ADDR, nr_bits) enables pointer tagging
   for the current process.

Because __NR_arch_prctl is defined in different headers, and no other
platforms need it at the moment, we only declare internal_arch_prctl()
on x86_64.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D129645