debugobjects: Fill_pool() returns void now

debugobjects: Fill_pool() returns void now

There was a return missed in 93d68a9f6a "debugobjects: Remove unused
return value from fill_pool()".  It makes gcc complain:

	lib/debugobjects.c: In function ‘fill_pool’:
	lib/debugobjects.c:98:4: warning: ‘return’ with a value, in
		function returning void [enabled by default]

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20120418112810.GA2669@elgon.mountain
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>