gobject-introspection: replace prelink-rtld with objdump -p

g-i internally processes the output with regexes, and seems
happy with what objdump is printing. It only needs to resolve
the library name as passed to the linker to the library file name.
Also recursive resolution (that ldd is doing and objdump is not)
is not necessary.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>