Handle memory error in print_insn_rl78_common

Handle memory error in print_insn_rl78_common

Nowadays, memory error in rl78 disassembly is not handled, so if I
start a fresh GDB, and disassemble,

(gdb) set architecture rl78
The target architecture is assumed to be rl78
(gdb) disassemble 0x0,+4
Dump of assembler code from 0x0 to 0x4:
   0x00000000:	nop
   0x00000001:	nop
   0x00000002:	nop
   0x00000003:	nop

the output is wrong.  This patch adds code to call dis->memory_error_func
on memory error, and longjmp to print_insn_rl78_common.  With this
patch applied,

(gdb) set architecture rl78
The target architecture is assumed to be rl78
(gdb) disassemble 0,+4
Dump of assembler code from 0x0 to 0x4:
   0x00000000:	Cannot access memory at address 0x0

opcodes:

2016-12-12  Yao Qi  <yao.qi@linaro.org>

	* rl78-dis.c: Include <setjmp.h>.
	(struct private): New.
	(rl78_get_byte): Check return value of read_memory_func, and
	call memory_error_func and OPCODES_SIGLONGJMP on error.
	(print_insn_rl78_common): Call OPCODES_SIGJMP.