RISC-V Disassembler

The RISC-V disassembler has no dependencies outside of the 'disas'
directory so it can be applied independently. The majority of the
disassembler is machine-generated from instruction set metadata:

- https://github.com/michaeljclark/riscv-meta

Expected checkpatch errors for consistency and brevity reasons:

ERROR: line over 90 characters
ERROR: trailing statements should be on next line
ERROR: space prohibited between function name and open parenthesis '('

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Michael Clark <mjc@sifive.com>

disas/Makefile.objs

@@ -17,6 +17,7 @@ common-obj-$(CONFIG_MIPS_DIS) += mips.o
 common-obj-$(CONFIG_NIOS2_DIS) += nios2.o
 common-obj-$(CONFIG_MOXIE_DIS) += moxie.o
 common-obj-$(CONFIG_PPC_DIS) += ppc.o
+common-obj-$(CONFIG_RISCV_DIS) += riscv.o
 common-obj-$(CONFIG_S390_DIS) += s390.o
 common-obj-$(CONFIG_SH4_DIS) += sh4.o
 common-obj-$(CONFIG_SPARC_DIS) += sparc.o