Staging: zram: Rename ramzswap to zram in code

Automated renames in code:
 - rzs* -> zram*
 - RZS* -> ZRAM*
 - ramzswap* -> zram*

Manual changes:
 - Edited comments/messages mentioning "swap"

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>