This patch fixes:
lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.h:34:5:
error: default label in switch which covers all enumeration values
[-Werror,-Wcovered-switch-default]
and:
lldb/source/Plugins/Instruction/RISCV/EmulateInstructionRISCV.cpp:194:21:
error: comparison of integers of different signs: 'int' and 'size_t'
(aka 'unsigned long') [-Werror,-Wsign-compare]