gcc: enable fdiv/fsqrt by default

Author: Andrew Waterman

gcc/gcc/config/riscv/riscv.opt

@@ -46,8 +46,12 @@ msoft-float
 Target Report RejectNegative Mask(SOFT_FLOAT_ABI)
 Prevent the use of all hardware floating-point instructions
 
+mno-fdiv
+Target Report RejectNegative Mask(NO_FDIV)
+Don't use hardware floating-point divide and square root instructions
+
 mfdiv
-Target Report RejectNegative Mask(FDIV)
+Target Report RejectNegative InverseMask(NO_FDIV, FDIV)
 Use hardware floating-point divide and square root instructions
 
 march=