arm: omap2plus: move NAND_BLOCK_SIZE out of boards

Several boards defining mtd partitions also defined NAND_BLOCK_SIZE as
SZ_128K. Move the define to common-board-devices.h

This removes multiple defines of NAND_BLOCK_SIZE.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/common-board-devices.h

@@ -1,6 +1,8 @@
 #ifndef __OMAP_COMMON_BOARD_DEVICES__
 #define __OMAP_COMMON_BOARD_DEVICES__
 
+#define NAND_BLOCK_SIZE	SZ_128K
+
 struct twl4030_platform_data;
 struct mtd_partition;