OPTABS: Extend the number of expanding instructions pattern

OPTABS: Extend the number of expanding instructions pattern

We (RVV) is going to add a rounding mode operand into floating-point
instructions which have 11 operands.

Since we are going have intrinsic that is adding rounding mode argument:
https://github.com/riscv-non-isa/rvv-intrinsic-doc/pull/226

This is the patch that is adding rounding mode operand in RISC-V port:
https://gcc.gnu.org/pipermail/gcc-patches/2023-May/618573.html
You can see there are 11 operands in these patterns.

gcc/ChangeLog:

	* optabs.cc (maybe_gen_insn): Add case to generate instruction
	that has 11 operands.

Signed-off-by: Juzhe-Zhong <juzhe.zhong@rivai.ai>