sh: Set the cfa_offset to 0 if we see a DW_CFA_def_cfa_register op

The way that the CFA is calculated can change as we progress through a
function. If we see a DW_CFA_def_cfa_register op we need to reset the
frame's cfa_offset value which may have been previously setup.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/dwarf.c

@@ -449,6 +449,7 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
 			count = dwarf_read_uleb128(current_insn,
 						   &frame->cfa_register);
 			current_insn += count;
+			frame->cfa_offset = 0;
 			frame->flags |= DWARF_FRAME_CFA_REG_OFFSET;
 			break;
 		case DW_CFA_def_cfa_offset: