mtd: nand: Rename nand.h into rawnand.h

We are planning to share more code between different NAND based
devices (SPI NAND, OneNAND and raw NANDs), but before doing that
we need to move the existing include/linux/mtd/nand.h file into
include/linux/mtd/rawnand.h so we can later create a nand.h header
containing all common structure and function prototypes.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Peter Pan <peterpandong@micron.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Acked-by: Wenyou Yang <wenyou.yang@microchip.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Han Xu <han.xu@nxp.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Shawn Guo <shawnguo@kernel.org>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-By: Harvey Hunt <harveyhuntnexus@gmail.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Krzysztof Halasa <khalasa@piap.pl>