Further rearranged the rotm kernel for the different architectures.

Signed-off-by: tingbo.liao <tingbo.liao@starfivetech.com>

"fmov.d $f2, $f4" leaves all the bits higher than the 63-th bit
unpredictable but it's obvious that the following code uses the value of
those high bits.  We actually want to replicate the lower 64 bits here,
so we should use xvreplve0.d instead.

LA464 (Loongson 3[A-Z]-5000) happens to replicate them for us due to
some uarch internal details so the issue was not detected, but for LA664
(Loongson 3[A-Z]-6000) and future uarch we need to do things correctly
or we end up getting a lot of test failures.

Closes: https://bbs.aosc.io/t/topic/302
Signed-off-by: Xi Ruoyao <xry111@xry111.site>

LoongArch64: Enable cmake cross-compilation

Use microarchitecture name instead of meaningless strings to name the core,
the legacy core is still retained.
1. Rename LOONGSONGENERIC to LA64_GENERIC
2. Rename LOONGSON3R5 to LA464
3. Rename LOONGSON2K1000 to LA264

Loongarch64: Improving the Performance and Stability of dgemm

Initialize the registers to prevent sporadic errors.

Optimized sgemv and dgemv kernel LSX for LoongArch

LoongArch64: Fixed {s/d}amin LSX optimization