RISC-V: Bugfix vec_extract vls mode iterator restriction mismatch

RISC-V: Bugfix vec_extract vls mode iterator restriction mismatch

We have vec_extract pattern which takes ZVFHMIN as the mode
iterator of the VLS mode.  Aka V_VLS.  But it will expand to
pred_extract_first pattern which takes the ZVFH as the mode
iterator of the VLS mode.  AKa V_VLSF.  The mismatch will
result in one ICE similar as below:

error: unrecognizable insn:
   27 | }
      | ^
(insn 19 18 20 2 (set (reg:HF 150 [ _13 ])
        (unspec:HF [
                (vec_select:HF (reg:V4HF 134 [ _1 ])
                    (parallel [
                            (const_int 0 [0])
                        ]))
                (reg:SI 67 vtype)
            ] UNSPEC_VPREDICATE)) "compress_run-2.c":24:5 -1
     (nil))
during RTL pass: vregs
compress_run-2.c:27:1: internal compiler error: in extract_insn, at
recog.cc:2812
0x1a627ef _fatal_insn(char const*, rtx_def const*, char const*, int,
char const*)
        ../../../gcc/gcc/rtl-error.cc:108
0x1a62834 _fatal_insn_not_found(rtx_def const*, char const*, int, char
const*)
        ../../../gcc/gcc/rtl-error.cc:116
0x1a0f356 extract_insn(rtx_insn*)
        ../../../gcc/gcc/recog.cc:2812
0x159ee61 instantiate_virtual_regs_in_insn
        ../../../gcc/gcc/function.cc:1612
0x15a04aa instantiate_virtual_regs
        ../../../gcc/gcc/function.cc:1995
0x15a058e execute
        ../../../gcc/gcc/function.cc:2042

This patch would like to fix this issue by align the mode
iterator restriction to ZVFH.

The below test suites are passed for this patch.
1. The rv64gcv fully regression test.
2. The rv64gcv build with glibc.

	PR target/115456

gcc/ChangeLog:

	* config/riscv/autovec.md: Take ZVFH mode iterator instead of
	the ZVFHMIN for the alignment.
	* config/riscv/vector-iterators.md: Add 2 new iterator
	V_VLS_ZVFH and VLS_ZVFH.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pr115456-1.c: New test.

Signed-off-by: Pan Li <pan2.li@intel.com>