The toolchain prefix will most likely be site specific and is not
guaranteed to always be "mips-linux-gnu-", so simply don't specify one.
A quick "git grep" shows this to be consistent amongst other cross
compiled targets.

Similarly, the site specific initramfs source location should not be used,
since that won't exist for most people, and it prevents them from doing
coverage builds on the defconfigs, such as those done in linux-next and run
routinely by many others.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jayachandran C <jayachandranc@netlogicmicro.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3296/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>