python-numpy: also disable ARC HS with glibc

Building python-numpy on ARC HS with glibc fails due to missing FE_*
definitions in <fenv.h>. Therefore, python-numpy is only available on
ARC HS with a C library other than glibc.

Fixes:

  http://autobuild.buildroot.net/results/6b9a3310bb4f8c1fd7db0ef4476458b3eec2bf2e/



Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>