mtd: nand: omap_gpmc: Always use ready/busy pin

The functions to detect the state of the ready / busy signal is already
available but only used in the SPL case. Lets use it always, also for the
main U-Boot. As all boards should have this HW connection.

Testing on Siemens Draco (am335x) showed a small perfomance gain by using
this ready pin to detect the NAND chip state. Here the values tested on
Draco with Hynix 4GBit NAND:

Without NAND ready pin:

U-Boot# time nand read 80400000 0 400000

NAND read: device 0 offset 0x0, size 0x400000
4194304 bytes read: OK

time: 2.947 seconds, 2947 ticks

With NAND ready pin:

U-Boot# time nand read 80400000 0 400000

NAND read: device 0 offset 0x0, size 0x400000
4194304 bytes read: OK

time: 2.795 seconds, 2795 ticks

So an increase of approx. 5%.
Signed-off-by: NStefan Roese <sr@denx.de>
Cc: Tom Rini <trini@ti.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Roger Meier <r.meier@siemens.com>
Cc: Samuel Egli <samuel.egli@siemens.com>

drivers/mtd/nand/omap_gpmc.c

@@ -73,14 +73,11 @@ static void omap_nand_hwcontrol(struct mtd_info *mtd, int32_t cmd,
 		writeb(cmd, this->IO_ADDR_W);
 }
 
-#ifdef CONFIG_SPL_BUILD
 /* Check wait pin as dev ready indicator */
-static int omap_spl_dev_ready(struct mtd_info *mtd)
+static int omap_dev_ready(struct mtd_info *mtd)
 {
 	return gpmc_cfg->status & (1 << 8);
 }
-#endif
-
 
 /*
  * gen_true_ecc - This function will generate true ECC value, which
@@ -887,7 +884,9 @@ int board_nand_init(struct nand_chip *nand)
 		nand->read_buf = nand_read_buf16;
 	else
 		nand->read_buf = nand_read_buf;
-	nand->dev_ready = omap_spl_dev_ready;
 #endif
+
+	nand->dev_ready = omap_dev_ready;
+
 	return 0;
 }