PAGE_READ is used by RISC-V arch code included through mm headers,
and it makes sense to bring in a prefix on these in the driver.

drivers/mtd/nand/raw/qcom_nandc.c:153: warning: "PAGE_READ" redefined
 #define PAGE_READ   0x2
In file included from include/linux/memremap.h:7,
                 from include/linux/mm.h:27,
                 from include/linux/scatterlist.h:8,
                 from include/linux/dma-mapping.h:11,
                 from drivers/mtd/nand/raw/qcom_nandc.c:17:
arch/riscv/include/asm/pgtable.h:48: note: this is the location of the previous definition

Caught by riscv allmodconfig.
Signed-off-by: NOlof Johansson <olof@lixom.net>
Reviewed-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@bootlin.com>