libdw: Recognize .debug_dwp section in scn_dwarf_type as TYPE_DWO

libdw: Recognize .debug_dwp section in scn_dwarf_type as TYPE_DWO

dwarf_begin_elf tries to guess what type of Dwarf we have. When it
sees a .debug_dwp section it assumed it was TYPE_PLAIN instead of
TYPE_DWO and would try to find more "plain" .debug sections (ignoring
other .dwo sections). This would cause it to not detect any debug
sections in a .dwp file containing a .debug_dwp section.

	* libdw/dwarf_begin_elf.c (scn_dwarf_type): Recognize
	.debug_dwp or .zdebug_dwp sections.

Signed-off-by: Mark Wielaard <mark@klomp.org>