RISC-V: Add support for Smcdeleg and Ssccfg extensions.

RISC-V: Add support for Smcdeleg and Ssccfg extensions.

This patch rebases the original patch from Nelson's implement[1].

Added new extension Smcdeleg and Ssccfg with a new CSR, scountinhibit.[2]

Co-Authored-By: Nelson Chu  <nelson@rivosinc.com>
Co-Authored-By: Jiawei Chen <jiawei@iscas.ac.cn>
[1] https://patchwork.sourceware.org/project/binutils/patch/20240620045359.47513-1-nelson@rivosinc.com/
[2] https://github.com/riscvarchive/riscv-smcdeleg-ssccfg/releases/tag/v1.0.0

bfd/ChangeLog:

	* elfxx-riscv.c: New extensions.

gas/ChangeLog:

	* NEWS: Mention new extensions.
	* config/tc-riscv.c (enum riscv_csr_class): New CSR class.
	(riscv_csr_address): Add support for Ssccfg.
	* testsuite/gas/riscv/csr-version-1p10.d: New test for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p10.l: New warning for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p11.d: New test for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p11.l: New warning for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p12.d: New test for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p12.l: New warning for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p13.d: New test for Ssccfg CSR.
	* testsuite/gas/riscv/csr-version-1p13.l: New warning for Ssccfg CSR.
	* testsuite/gas/riscv/csr.s: New Ssccfg CSR.
	* testsuite/gas/riscv/imply.d: New imply check.
	* testsuite/gas/riscv/imply.s: New implies.
	* testsuite/gas/riscv/march-help.l: New helping info.

include/ChangeLog:

        * opcode/riscv-opc.h (CSR_SCOUNTINHIBIT): New CSR address.
        (DECLARE_CSR): Add Ssccfg CSR.