target-mips: remove wrong checks for recip.fmt and rsqrt.fmt

Instructions recip.{s|d} and rsqrt.{s|d} do not require 64-bit FPU neither
they require any particular mode for its FPU. This patch removes the checks
that may break a program that uses these instructions.

Signed-off-by: Petar Jovanovic <petar.jovanovic@imgtec.com>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
