lib: devres: add annotations for #endif

While working on devres, I found those make navigating the code a tad
easier.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>