math: Remove i386 ilogb/ilogbf/llogb/llogbf

math: Remove i386 ilogb/ilogbf/llogb/llogbf

The new float and double implementation does not required an
extra function call and error handling uses math_err function,
which results in better performance on i386 as well.

With gcc-14 on AMD AMD Ryzen 9 5900X, master shows:

$ ./benchtests/bench-ilogb
  "ilogb": {
   "subnormal": {
    "duration": 3.68863e+09,
    "iterations": 1.72228e+08,
    "max": 89.2995,
    "min": 21.016,
    "mean": 21.4171
   },
   "normal": {
    "duration": 3.68878e+09,
    "iterations": 1.72948e+08,
    "max": 78.6065,
    "min": 21.127,
    "mean": 21.3288
   }
  }
$ ./benchtests/bench-ilogbf
  "ilogbf": {
   "subnormal": {
    "duration": 3.68835e+09,
    "iterations": 1.66716e+08,
    "max": 46.953,
    "min": 21.793,
    "mean": 22.1236
   },
   "normal": {
    "duration": 3.68784e+09,
    "iterations": 1.66168e+08,
    "max": 46.9715,
    "min": 21.904,
    "mean": 22.1935
   }
  }

While with this patch:

$ ./benchtests/bench-ilogb
  "ilogb": {
   "subnormal": {
    "duration": 3.68134e+09,
    "iterations": 4.17516e+08,
    "max": 32.5045,
    "min": 8.3245,
    "mean": 8.81723
   },
   "normal": {
    "duration": 3.6677e+09,
    "iterations": 6.79468e+08,
    "max": 50.9305,
    "min": 5.3465,
    "mean": 5.3979
   }
}
$ ./benchtests/bench-ilogbf
  "ilogbf": {
   "subnormal": {
    "duration": 3.67553e+09,
    "iterations": 5.11032e+08,
    "max": 35.927,
    "min": 7.0485,
    "mean": 7.19237
   },
   "normal": {
    "duration": 3.66877e+09,
    "iterations": 6.556e+08,
    "max": 26.3625,
    "min": 5.5315,
    "mean": 5.59605
   }
 }

Checked on i686-linux-gnu.

Reviewed-by: Wilco Dijkstra  <Wilco.Dijkstra@arm.com>