nand: remove CONFIG_SYS_NAND_PAGE_SIZE

We only need to read in the size of struct image_header and thus don't
need to know the page size of the nand device.

Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Stefano Babic <sbabic@denx.de>
Acked-by: Scott Wood <scottwood@freescale.com>

common/spl/spl_nand.c

@@ -76,7 +76,7 @@ void spl_nand_load_image(void)
 #endif
 	/* Load u-boot */
 	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
-		CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
+		sizeof(*header), (void *)header);
 	spl_parse_image_header(header);
 	nand_spl_load_image(CONFIG_SYS_NAND_U_BOOT_OFFS,
 		spl_image.size, (void *)spl_image.load_addr);