sched, cpusets: fix warning in kernel/cpuset.c

this warning:

  kernel/cpuset.c: In function ‘generate_sched_domains’:
  kernel/cpuset.c:588: warning: ‘ndoms’ may be used uninitialized in this function

triggers because GCC does not recognize that ndoms stays uninitialized
only if doms is NULL - but that flow is covered at the end of
generate_sched_domains().

Help out GCC by initializing this variable to 0. (that's prudent anyway)

Also, this function needs a splitup and code flow simplification:
with 160 lines length it's clearly too long.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/cpuset.c

@@ -585,7 +585,7 @@ static int generate_sched_domains(cpumask_t **domains,
 	int i, j, k;		/* indices for partition finding loops */
 	cpumask_t *doms;	/* resulting partition; i.e. sched domains */
 	struct sched_domain_attr *dattr;  /* attributes for custom domains */
-	int ndoms;		/* number of sched domains in result */
+	int ndoms = 0;		/* number of sched domains in result */
 	int nslot;		/* next empty doms[] cpumask_t slot */
 
 	doms = NULL;