Prevent a potential illegal memory access in readelf when parsing a note with a zero...

Prevent a potential illegal memory access in readelf when parsing a note with a zero name size.

	PR 24131
	* readelf.c (process_notes_at): Prevent an illegal memory access
	when the note's namesize is zero.
	(decode_tic6x_unwind_bytecode): Add code to handle the case where
	no registers are specified in a frame pop instruction.