gst1-plugins-good: v4l2 plugin needs kernel headers 3.0+

Fixes http://autobuild.buildroot.net/results/284/284313e660c3c9fad891fd71aa56ca5751946dc6/



For the multi planar api (mp_pix). It was actually added in 2.6.39 (commit
f8f3914cf9), but we only have symbols for 3.x kernels, so use 3.0 instead.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>