Renamed EXTRACT and ENCODE macros.

The existing CORE-V macro names are inconsistent (inherited
from the PULP project). This series of commits provides
more meaningful names.

bfd/ChangeLog.COREV:

        * elfnn-riscv.c (perform_relocation): Renamed macros for clarity -
        ENCODE_I1TYPE_UIMM -> ENCODE_CV_HWLP_UIMM5
        ENCODE_I1TYPE_LN   -> ENCODE_CV_HWLP_LN
        * elfxx-riscv.c: Renamed macros for clarity -
        EXTRACT_I1TYPE_UIMM-> EXTRACT_CV_HWLP_UIMM5
        EXTRACT_I1TYPE_LN  -> EXTRACT_CV_HWLP_LN
        EXTRACT_ITYPE_UIMM -> EXTRACT_CV_HWLP_UIMM12

gas/ChangeLog.COREV:

        * config/tc-riscv.c (validate_riscv_insn): Renamed macros for clarity -
        ENCODE_I1TYPE_UIMM -> ENCODE_CV_HWLP_UIMM5
        ENCODE_I1TYPE_LN   -> ENCODE_CV_HWLP_LN
        * config/tc-riscv.c (md_apply_fix): Renamed macros for clarity -
        ENCODE_I1TYPE_UIMM -> ENCODE_CV_HWLP_UIMM5

include/ChangeLog.COREV:

        * opcode/riscv.h (riscv_pred_succ): Renamed macros for clarity -
        ENCODE_I1TYPE_UIMM -> ENCODE_CV_HWLP_UIMM5
        ENCODE_I1TYPE_LN   -> ENCODE_CV_HWLP_LN
        EXTRACT_I1TYPE_UIMM-> EXTRACT_CV_HWLP_UIMM5
        EXTRACT_I1TYPE_LN  -> EXTRACT_CV_HWLP_LN
        EXTRACT_ITYPE_UIMM -> EXTRACT_CV_HWLP_UIMM12

opcodes/ChangeLog.COREV:

        * riscv-opc.c (print_insn_args): Renamed macros for clarity -
        EXTRACT_I1TYPE_UIMM-> EXTRACT_CV_HWLP_UIMM5
        EXTRACT_ITYPE_UIMM -> EXTRACT_CV_HWLP_UIMM12

Signed-off-by: Mary Bennett <mary.bennett@embecosm.com>