RISC-V: Hypervisor ext: drop Privileged Spec 1.9.1 implementation/tests

This makes way for a clean 1.12 based Hypervisor Ext support.

There are no known implementors of 1.9.1 H-ext. (Per Jim, kendryte k210
is based on priv spec 1.9.1, but it seems unlikely that they implemented
H-ext).

Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Nelson Chu <nelson.chu@sifive.com>

gas/
	* testsuite/gas/riscv/csr-dw-regnums.d: Drop the hypervisor csrs
	defined in the privileged spec 1.9.1.
	* testsuite/gas/riscv/csr-dw-regnums.s: Likewise.
	* testsuite/gas/riscv/priv-reg-fail-read-only-01.s: Likewise.
	* testsuite/gas/riscv/priv-reg-fail-version-1p10.l: Likewise.
	* testsuite/gas/riscv/priv-reg-fail-version-1p11.l: Likewise.
	* testsuite/gas/riscv/priv-reg-version-1p10.d: Likewise.
	* testsuite/gas/riscv/priv-reg-version-1p11.d: Likewise.
	* testsuite/gas/riscv/priv-reg-version-1p9p1.d: Likewise.
	* testsuite/gas/riscv/priv-reg.s: Likewise.
include/
	* opcode/riscv-opc.h: Drop the hypervisor csrs defined in the
	privileged spec 1.9.1.