PPC debug_line support

[Franz Sirl]

Hi,

this patch adds debug_line support for PPC, please someone apply it after 
review.

Franz.

	* config/tc-ppc.c (md_pseudo_table): Add .file and .loc.
	(md_assemble): Call dwarf2_emit_insn.
	(shlib): Fix typo SHILB -> SHLIB.
	(md_parse_option): Likewise.
	(ppc_elf_validate_fix): Likewise:
	* config/tc-ppc.h (DWARF2_LINE_MIN_INSN_LENGTH): New.