staging: Add Snappy compression support to zram (alt)

Google's Snappy data compression library is a faster alternative to LZO,
optimized for x86-64. On compressible input it compresses ~2.5x faster than LZO
and decompresses ~1.5-2x faster than LZO. On incompressible input, it skips the
input at 100x faster than LZO and decompresses ~4x faster than LZO.
It is released under BSD license.
This is a kernel port from user space C++ code.
The current intended use is with zram (see next patch in series).

Signed-off-by: Zeev Tarantov <zeev.tarantov@gmail.com>
Modified for use with patched Linux-Next ZRAM drivers by faux123

Conflicts:
	drivers/staging/zram/Kconfig
	drivers/staging/zram/zram_drv.c
zram: Simplify zram disk resizing interface

Also remove unnecessary messages.

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Reviewed-by: Jerome Marchand <jmarchan@redhat.com>
Add ZRAM_FOR_ANDROID, with all of the bits

Conflicts:
	drivers/staging/zram/zram_drv.c
zram_sysfs: num_devices was renamed to zram_num_devices
zram: forgot to fix the name of zram_num_devices in zram_drv.h
zram: last time
fix zram_for_android compiling