benchtests: Move libmvec benchtest inputs to benchtests directory

This allows other targets to use the same inputs for their own libmvec
microbenchmarks without having to duplicate them in their own
subdirectory.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

sysdeps/x86_64/fpu/scripts/bench_libmvec.py

@@ -396,7 +396,7 @@ def parse_file(func_types):
 
   func = func_types[-1]
   try:
-    with open('../sysdeps/x86_64/fpu/libmvec-%s-inputs' % func) as f:
+    with open('../benchtests/libmvec/%s-inputs' % func) as f:
       for line in f:
         # Look for directives and parse it if found.
         if line.startswith('##'):