[ARC] 24 bit reloc and overflow detection fix.

[ARC] 24 bit reloc and overflow detection fix.

bfd/
2016-04-05  Cupertino Miranda  <cmiranda@synopsys.com>

	* elf32-arc.c (name_for_global_symbol): Changed assert.
	(get_replace_function): Created.:
	(struct arc_relocation_data): Changed to signed types.
	(defines S, L, P, PDATA): Casted to signed type.
	(defines SECTSTART, _SDA_BASE_, TLS_REL): Likewise.
	(PRINT_DEBUG_RELOC_INFO_BEFORE): Changed.
	(arc_do_relocation): Changed.

include/
2016-04-05  Cupertino Miranda  <cmiranda@synopsys.com>

	* opcode/arc-func.h (replace_bits24): Changed.
	(replace_bits24_be): Created.