python: Do not verify whether libiio is installed when cross-compiling
python: Do not verify whether libiio is installed when cross-compiling

This should fix #561

Signed-off-by: Julien Malik <6c8b09f3729f9e0a660bb212765f608b16e03e00@paraiso.me>

analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio