package/python-greenlet: enable only on supported architectures
Fixes:
http://autobuild.buildroot.net/results/
4161bfcd9577cdc6b9795fc3d6903f3bcc124f99/
http://autobuild.buildroot.net/results/
be709462bbab54e4f405302d54d157218f867939/
http://autobuild.buildroot.net/results/
b0ca52e3948cbbc5bb8c6ce08932e355653b08d7/
http://autobuild.buildroot.net/results/
cd748aa26fdabcef72a581e1fe26edac14d07d2d/
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>