RISC-V: Use a tab rather than space with FSFLAGS

RISC-V: Use a tab rather than space with FSFLAGS

Consistently use a tab rather than a space as the separator between the
assembly instruction mnemonic and its operand with FSFLAGS instructions
produced with the unordered FP comparison RTL insns.

	gcc/
	* config/riscv/riscv.md
	(*f<quiet_pattern>_quiet<ANYF:mode><X:mode>4_default)
	(*f<quiet_pattern>_quiet<ANYF:mode><X:mode>4_snan): Emit a tab
	rather than space with FSFLAGS.