Revert DOT kernel changes from #1834

as the failures seen on Loongson3A appear to be limited to DSDOT/SDSDOT (i.e. my hackish "fix" from #1684)

kernel/mips64/KERNEL

@@ -1,9 +1,9 @@
 CAXPYKERNEL = ../mips/zaxpy.c
 ZAXPYKERNEL = ../mips/zaxpy.c
-SROTKERNEL = ../mips/rot.c
-DROTKERNEL = ../mips/rot.c
-CROTKERNEL = ../mips/zrot.c
-ZROTKERNEL = ../mips/zrot.c
+SROTKERNEL  = ../mips/rot.c
+DROTKERNEL  = ../mips/rot.c
+CROTKERNEL  = ../mips/zrot.c
+ZROTKERNEL  = ../mips/zrot.c
 CSWAPKERNEL = ../mips/zswap.c
 ZSWAPKERNEL = ../mips/zswap.c