ARM: omap: move board specific NAND configs out from ti_armv7_common.h

This patch moves some board specific NAND configs:
- FROM: generic config file 'ti_armv7_common.h'
- TO:   individual board config files using these configs.
So that each board can independently set the value as per its design.

Following configs are affected in this patch:
  CONFIG_SYS_NAND_U_BOOT_OFFS: <refer doc/README.nand>
  CONFIG_CMD_SPL_NAND_OFS: <refer doc/README.falcon>
  CONFIG_SYS_NAND_SPL_KERNEL_OFFS: <refer doc/README.falcon>
  CONFIG_CMD_SPL_WRITE_SIZE: <refer doc/README.falcon>

This patch also updates documentation for few of above NAND configs.

Signed-off-by: Pekon Gupta <pekon@ti.com>
diff --git a/include/configs/omap3_beagle.h b/include/configs/omap3_beagle.h
index e951389..fe07990 100644
--- a/include/configs/omap3_beagle.h
+++ b/include/configs/omap3_beagle.h
@@ -303,5 +303,11 @@
 #define CONFIG_SYS_NAND_ECCBYTES	3
 #define CONFIG_NAND_OMAP_ECCSCHEME	OMAP_ECC_HAM1_CODE_HW
 #define CONFIG_SYS_NAND_U_BOOT_OFFS	0x80000
+/* NAND: SPL falcon mode configs */
+#ifdef CONFIG_SPL_OS_BOOT
+#define CONFIG_CMD_SPL_NAND_OFS		0x240000
+#define CONFIG_SYS_NAND_SPL_KERNEL_OFFS	0x280000
+#define CONFIG_CMD_SPL_WRITE_SIZE	0x2000
+#endif
 
 #endif /* __CONFIG_H */