This replaces kmalloc + memset by a call to kzalloc

This also fixes one checkpatch.pl issue in the process.

This improvement was suggested by "make coccicheck"
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>