ia64: Use generic exp10f

The generic implementation is slight worse (Itanium(R) Processor 9020):

Before new code:
  "exp10f": {
   "workload-spec2017.wrf (adapted)": {
    "duration": 3.61582e+08,
    "iterations": 2.384e+07,
    "reciprocal-throughput": 14.8334,
    "latency": 15.5006,
    "max-throughput": 6.74153e+07,
    "min-throughput": 6.45136e+07
   }
  }

With new code:
  "exp10f": {
   "workload-spec2017.wrf (adapted)": {
    "duration": 3.85549e+08,
    "iterations": 2.384e+07,
    "reciprocal-throughput": 15.8391,
    "latency": 16.5056,
    "max-throughput": 6.31348e+07,
    "min-throughput": 6.05857e+07
   }
  }

However it fixes all the issues on both:

  math/test-float-exp10
  math/test-float32-exp10

(all the issues wrong results for non default rounding modes).

The existing ia64 libm interface uses matherrf and matherrl in addition
to matherr for SVID error handling. However, there is no such error
handling support for exp10f in ia64 libm.  So replacing it with the
generic implementation should be fine.

Checked on ia64-linux-gnu.