[AArch64][SME]Update intrinsic interface for ld1/st1 (#65582)

The new ACLE PR#225[1] now combines the slice parameters for some
builtins. 
Slice specifies the ZA slice number directly and needs to be explicity
implemented by the "user" with the base register plus the immediate
offset

[1]https://github.com/ARM-software/acle/pull/225/files