[AArch64] Cast predicate operand of SVE gather loads/scater stores to the...

[AArch64] Cast predicate operand of SVE gather loads/scater stores to the parameter type of the intrinsic (NFC) (#71289)

When emitting LLVM IR for gather loads/scatter stores, the predicate
parameter is cast to a type that depends on the loaded, resp. stored
type. That's correct for operation where we have a predicate per lane,
however it is not correct for quadword loads and stores (`LD1Q`, `ST1Q`)
where the predicate is per 128-bit chunk, independent from the ACLE
intrinsic type.

This can be universally handled by cast to the corresponding parameter
type of the intrinsic. The intrinsic itself should be defined in a way
that enforces relations between parameter types.