drivers/char/ipmi/Makefile: replace the use of <module>-objs with <module>-y

Changed <module>-objs to <module>-y in Makefile.

Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>