OMAP3: FLASH: Move Flash specific device info in aseparate board file

This patch does the following
	moves flash specific code to a new file board-3430sdp-flash.c
	adds support for 3430 ES2 SDP changes for ethernet
	changes the check in gpmc to OMAP34XX as same address is valid.
Signed-off-by: Rohit Choraria <rohitkc@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>