Multiply Accumulate Version 2 Instructions and Tests Encodings Updated

	include/opcode:
            * riscv-opc.h: Added corresponding MATCH and MASK
              macros for Multiply Accumulate.

	gas/testsuite/gas/riscv:
	    * gas/testsuite/gas/riscv/cv-mac-mac.d: Test Encodings Updated.
	    * gas/testsuite/gas/riscv/cv-mac-machhsn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-machhsrn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-machhun.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-machhurn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-macsn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-macsrn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-macun.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-macurn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-march-rv32i-xcorev.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-msu.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulhhsn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulhhun.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulhhurn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulsn.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulun.d: Likewise.
	    * gas/testsuite/gas/riscv/cv-mac-mulurn.d: Likewise.

Signed-off-by: Nandni Jamnadas <nandni.jamnadas@embecosm.com>