libs: openblas: use GENERIC for MIPS{EL} and MIPS24K for CPU_TYPE == 24kc
Up until now, we were defaulting to MIPS24K for all MIPS archs.
But, we should use the GENERIC target for MIPS{EL} and the MIPS24K target
for the 24kc CPU_TYPE.
Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>