selftests/memfd: Run test on all architectures

selftests/memfd: Run test on all architectures

Remove the dependence on x86 to run the memfd test. Verfied on 32-bit powerpc.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Change-Id: I4e3a0d311842f5d0327abdb6bb8ce3ba1460f902
Origin: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ce6a144a0d01c6628496e4c0d18fbf3a0362cc67
Backported-by: Maciej Wereski <m.wereski@partner.samsung.com>
Signed-off-by: Maciej Wereski <m.wereski@partner.samsung.com>