libdwfl: Fix out of memory handling in link_map.c report_r_debug

libdwfl: Fix out of memory handling in link_map.c report_r_debug

In report_r_debug we don't fully handle an out of memory condition
when trying to allocate memory for the r_debug_info_module struct.
Deallocated allocated buffers and return -1 immediately instead of
trying to continue.

	* libdwfl/link_map.c (report_r_debug): Call release_buffer
	with -1 and return on malloc failure.

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