-fno-plt and musl-libc patches already get upstream, then dropped
in GCC 6. Other patches are almost identical compared to GCC 5.4.

Compile and run tested on ar71xx/Qihoo C301 and
mvebu/Linksys WRT1900ac v1

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [cleanups/fixes]