staging: zsmalloc: zsmalloc memory allocation library

This patch creates a new memory allocation library named
zsmalloc.

NOTE: zsmalloc currently depends on SPARSEMEM for the MAX_PHYSMEM_BITS
value needed to determine the format of the object handle. There may
be a better way to do this.  Feedback is welcome.

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>