RISC-V: update match_func of cm.jt/cm.jalt to spec 1.0

ld/ChangeLog:

	* testsuite/ld-riscv-elf/zc-zcmt-jump-table-2.d: Update testcase.
	* testsuite/ld-riscv-elf/zc-zcmt-jump-table.d: Ditto.

opcodes/ChangeLog:

	* riscv-opc.c (match_cm_jt): Update valid index range for cm.jt.
	(match_cm_jalt): Ditto.