x86/platform/uv: Replace kmalloc() & memset with kzalloc()

This was found using coccicheck.

Signed-off-by: Alexandru Gheorghiu <gheorghiuandru@gmail.com>
Link: http://lkml.kernel.org/r/1362822043-15559-1-git-send-email-gheorghiuandru@gmail.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>