RISC-V: Add 'Smcntrpmf' extension and its CSRs

RISC-V: Add 'Smcntrpmf' extension and its CSRs

This commit adds now stable and approved 'Smcntrpmf' extension defined by
the RISC-V Cycle and Instret Privilege Mode Filtering specification.

Note that, because mcyclecfg and minstretcfg CSRs conflict with the
privileged specification version 1.9.1, CSRs for this extension are only
enabled on the privileged specification version 1.10 or later.

By checking the base privileged specification, we no longer need to change
the design of base CSR handling.

This is based on the specification version v1.0_rc1 (Frozen):
<https://github.com/riscv/riscv-smcntrpmf/commit/32b752c40d59c1b5e95de83399c1f54be6669163>

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_implicit_subsets): Add implication rule from
	the new 'Smcntrpmf' extension.  (riscv_supported_std_s_ext): Add
	'Smcntrpmf' to the supported S extension list.

gas/ChangeLog:

	* config/tc-riscv.c (enum riscv_csr_class): Add new CSR classes
	CSR_CLASS_SMCNTRPMF and CSR_CLASS_SMCNTRPMF_32.
	(riscv_csr_address): Add handling for new CSR classes.
	* testsuite/gas/riscv/csr-dw-regnums.s: Add new CSRs.  Move
	"mscounteren" and "mhcounteren" CSRs and note that they are now
	aliases.
	* testsuite/gas/riscv/csr-dw-regnums.d: Reflect the change.
	* testsuite/gas/riscv/csr.s: Add new CSRs.  Move "mscounteren"
	and "mhcounteren" CSRs and note that they are now reused for
	the 'Smcntrpmf' extension.
	* testsuite/gas/riscv/csr-version-1p9p1.d: Reflect the changes of
	csr.s.
	* testsuite/gas/riscv/csr-version-1p9p1.l: Likewise.
	* testsuite/gas/riscv/csr-version-1p10.d: Likewise.
	* testsuite/gas/riscv/csr-version-1p10.l: Likewise.
	* testsuite/gas/riscv/csr-version-1p11.d: Likewise.
	* testsuite/gas/riscv/csr-version-1p11.l: Likewise.
	* testsuite/gas/riscv/csr-version-1p12.d: Likewise.
	* testsuite/gas/riscv/csr-version-1p12.l: Likewise.

include/ChangeLog:

	* opcode/riscv-opc.h: Add new CSRs noting that this extension is
	incompatible with the privileged specification version 1.9.1.
	Move "mscounteren" and "mhcounteren" CSRs, make them aliases and
	reuse the CSR numbers from the 'Smcntrpmf' extension.
	(CSR_MSCOUNTEREN, CSR_MHCOUNTEREN) Remove as "mscounteren" and
	"mhcounteren" are now aliases and new CSR macros are used instead.
	(CSR_MCYCLECFG, CSR_MINSTRETCFG, CSR_MCYCLECFGH, CSR_MINSTRETCFGH):
	New CSR macros.