Newer GCC versions are reported to improve code size on various ARM
devices, which is why newer u-boot versions require them now.
There have also been user reports of data corruption issues fixed on
MIPS by updating from GCC 5 to GCC 7.
This update was previously held up by these two MIPS compile issues,
which have since been fixed:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83496https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84790
Signed-off-by: Felix Fietkau <nbd@nbd.name>