Add .cfi_val_offset GAS command.

Add .cfi_val_offset GAS command.

This patch adds support for .cfi_val_offset GAS pseudo command which
maps to DW_CFA_val_offset and DW_CFA_val_offset_sf.

gas/ChangeLog:

2016-09-29  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* doc/as.texinfo: Add docu for .cfi_val_offset.
	* dw2gencfi.c (cfi_add_CFA_val_offset): New function.
	(dot_cfi): Add case for DW_CFA_val_offset.
	(output_cfi_insn): Likewise.
	(cfi_pseudo_table): Add entry for cfi_val_offset.
	* dw2gencfi.h: Add prototype for cfi_add_CFA_val_offset.
	* testsuite/gas/cfi/cfi-common-8.d: New test.
	* testsuite/gas/cfi/cfi-common-8.s: New test.
	* testsuite/gas/cfi/cfi.exp: Run cfi-common-8 testcase.

binutils/ChangeLog:

2016-09-29  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* dwarf.c (display_debug_frames): Adjust output line.