nand: Calculate SYS_NAND_BLOCK_PAGES (neeĢ SYS_NAND_PAGE_COUNT) automatically

Contrary to what the help message says, this is the number of pages per
block. Calculate it automatically based on SYS_NAND_BLOCK_SIZE and
SYS_NAND_PAGE_SIZE. To better reflect its semantics, rename it to
SYS_NAND_BLOCK_PAGES.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/mtd/nand/raw/atmel_nand.c b/drivers/mtd/nand/raw/atmel_nand.c
index 6b17e74..8332011 100644
--- a/drivers/mtd/nand/raw/atmel_nand.c
+++ b/drivers/mtd/nand/raw/atmel_nand.c
@@ -12,6 +12,7 @@
 
 #include <common.h>
 #include <log.h>
+#include <system-constants.h>
 #include <asm/gpio.h>
 #include <asm/arch/gpio.h>
 #include <dm/device_compat.h>
@@ -1258,7 +1259,7 @@
 static int nand_command(int block, int page, uint32_t offs, u8 cmd)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
-	int page_addr = page + block * CONFIG_SYS_NAND_PAGE_COUNT;
+	int page_addr = page + block * SYS_NAND_BLOCK_PAGES;
 	void (*hwctrl)(struct mtd_info *mtd, int cmd,
 			unsigned int ctrl) = this->cmd_ctrl;
 
@@ -1359,7 +1360,7 @@
 	if (nand_chip.select_chip)
 		nand_chip.select_chip(mtd, 0);
 
-	page_addr = page + block * CONFIG_SYS_NAND_PAGE_COUNT;
+	page_addr = page + block * SYS_NAND_BLOCK_PAGES;
 	hwctrl(mtd, NAND_CMD_ERASE1, NAND_CTRL_CLE | NAND_CTRL_CHANGE);
 	/* Row address */
 	hwctrl(mtd, (page_addr & 0xff), NAND_CTRL_ALE | NAND_CTRL_CHANGE);