[AArch64] Force __builtin_aarch64_fp[sc]r argument into a REG

[AArch64] Force __builtin_aarch64_fp[sc]r argument into a REG

The testcase triggered an ICE because the builtin expansion
code passed the output of expand_normal directly to the SET_FP[SC]R
generator, without forcing it into a register first.

gcc/
	* config/aarch64/aarch64-builtins.c (aarch64_expand_builtin): Force
	__builtin_aarch64_fp[sc]r arguments into a register.

gcc/testsuite/
	* gcc.target/aarch64/fpcr_fpsr_1.c: New file.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@228116 138bc75d-0d04-0410-961f-82ee72b054a4