arm: Fix sign of MVE predicate mve_pred16_t [PR 107674]
The ACLE defines mve_pred16_t as an unsigned short. This patch makes sure GCC
treats the predicate as an unsigned type, rather than signed.
gcc/ChangeLog:
PR target/107674
* config/arm/arm-builtins.cc (arm_simd_builtin_type): Rewrite to use
new qualifiers parameter and use unsigned short type for MVE predicate.
(arm_init_builtin): Call arm_simd_builtin_type with qualifiers
parameter.
(arm_init_crypto_builtins): Likewise.
gcc/testsuite/ChangeLog:
PR target/107674
* gcc.target/arm/mve/mve_vpt.c: New test.