i386: Force inputs to a register to avoid lowpart_subreg failure [PR104458]

Input operands can be in the form of:

	(subreg:DI (reg:V2SF 96) 0)

which chokes lowpart_subreg. Force inputs to a register, which is
preferable even when the input operand is from memory.

2022-02-09  Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog:

	PR target/104458
	* config/i386/i386-expand.cc (ix86_split_idivmod):
	Force operands[2] and operands[3] into a register..

gcc/testsuite/ChangeLog:

	PR target/104458
	* gcc.target/i386/pr104458.c: New test.