staging: hv: Remove NULL check before kfree

This patch was generated by the following semantic patch:
// <smpl>
@@ expression E; @@
- if (E != NULL) { kfree(E); }
+ kfree(E);

@@ expression E; @@
- if (E != NULL) { kfree(E); E = NULL; }
+ kfree(E);
+ E = NULL;
// </smpl>

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Mike Sterling <mike.sterling@microsoft.com>
Cc: Abhishek Kane <v-abkane@microsoft.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>