OpenBLAS

LoongArch64: Compatible with early internal toolchain

__loongarch_grlen and __loongarch_frlen were introduced in gcc version 8.3.0
(Loongnix 8.3.0-6.lnd.vec.31) internally within Loongson to standardize the
general and floating-point register widths. However, previous versions did
not have them, requiring additional checks to be added.