dwarf2: Pad size of .debug_line section.

dwarf2: Pad size of .debug_line section.

As all dwarf debug information is organized in octets, the size of all
dwarf sections must be aligned to OCTETS_PER_BYTE.  Most DWARF sections
meet this requirement, only the .debug_line section can reach an
arbitrary octet size.

In order to align the size to a multiple of OCTETS_PER_BYTE, the section
is padded with "nop" statements at the end.

	* dwarf2dbg.c (out_debug_line): Pad size of .debug_line section.