buildroot

configs/orangepipc: Use Linux 4.7.3

There's now an sun8i-h3-orangepi-pc dts, so we can use that and drop the
hack in the post-image script.

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