Use generic/dot.c for DSDOT on z13
The implementation in arm/dot.c has lower precision, as shown by the utest for dsdot.
@@ -49,6 +49,7 @@ SDOTKERNEL = ../arm/dot.c
DDOTKERNEL = ddot.c
CDOTKERNEL = ../arm/zdot.c
ZDOTKERNEL = zdot.c
+DSDOTKERNEL = ../generic/dot.c
SNRM2KERNEL = ../arm/nrm2.c
DNRM2KERNEL = ../arm/nrm2.c
