Merge branch 'BPF array map fixes and improvements'

Andrii Nakryiko says:

====================

Fix 32-bit overflow in value pointer calculations in BPF array map. And then
raise obsolete limit on array map value size. Add selftest making sure this is
working as intended.

v1->v2:
  - fix broken patch #1 (no mask_index use in helper, as stated in commit
    message; and add missing semicolon).
====================

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>