perf: append endianness argument to ld when building for MIPS

We need to pass an argument to ld for setting the endianness when
building it for MIPS architecture, otherwise the default one will always
be used (which is big endian) and the compilation for little endian will
always fail showing an error like this one:

LD    foo.o
mips-linux-gnu-ld: foo.o: compiled for a little endian system and target
is big endian

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>