owfs: disable PHP support

owfs: disable PHP support

Since we upgraded PHP to PHP 7.x, the PHP support of OWFS started
failing to build. Since we can hardly fix that on our own, the issue was
reported upstream (https://sourceforge.net/p/owfs/support-requests/32/)
and for now, we will disable PHP support in OWFS.

Fixes:

  http://autobuild.buildroot.net/results/fe6843ec53fbed452d2e38a8577a235f73abb8db/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>