Similar as [3/6], these intrinsics were implemented before the instruction
pattern "aarch64_rsqrts<mode>" added, that these intrinsics were implemented
through inline assembly.

This mirgrate the implementation to builtin.

gcc/
2016-05-23  Jiong Wang <jiong.wang@arm.com>

         * config/aarch64/aarch64-builtins.def (rsqrts): New builtins 
for modes
         VALLF.
         * config/aarch64/aarch64-simd.md (aarch64_rsqrts_<mode>3): 
Rename to
"aarch64_rsqrts<mode>".
         * config/aarch64/aarch64.c (get_rsqrts_type): Update gen* name.
         * config/aarch64/arm_neon.h (vrsqrtss_f32): Remove inline 
assembly.  Use
builtin.
         (vrsqrtsd_f64): Likewise.
         (vrsqrts_f32): Likewise.
         (vrsqrtsq_f32): Likewise.
         (vrsqrtsq_f64): Likewise.