Remove builtin function fma from utest_math_gen.py.
Remove builtin function fma from utest_math_gen.py.

Signed-off-by: Yi Sun <a7ab858552be010621b3b5c596bf4feb1309fb3c@intel.com>
Reviewed-by: "Yang, Rong R" <78759e37dc7114caed18f74e7515c5cb519dbf6d@intel.com>

ignatenkobrain/beignet,zhenyw/beignet,ignatenkobrain/beignet,wdv4758h/beignet,freedesktop-unofficial-mirror/beignet,freedesktop-unofficial-mirror/beignet,zhenyw/beignet,wdv4758h/beignet,ignatenkobrain/beignet,freedesktop-unofficial-mirror/beignet,ignatenkobrain/beignet,ignatenkobrain/beignet,zhenyw/beignet,freedesktop-unofficial-mirror/beignet,zhenyw/beignet,wdv4758h/beignet,wdv4758h/beignet,zhenyw/beignet,wdv4758h/beignet