mxs: reorganize source directory for easy sharing of code in i.MXS SoCs

Most code can be shared between i.MX23 and i.MX28 as both are from
i.MXS family; this source directory structure makes easy to share code
among them.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/boards.cfg b/boards.cfg
index 25b4981..467974b 100644
--- a/boards.cfg
+++ b/boards.cfg
@@ -179,9 +179,9 @@
 zmx25                        arm         arm926ejs   zmx25               syteco         mx25
 imx27lite                    arm         arm926ejs   imx27lite           logicpd        mx27
 magnesium                    arm         arm926ejs   imx27lite           logicpd        mx27
-apx4devkit                   arm         arm926ejs   -                   bluegiga       mx28
-m28evk                       arm         arm926ejs   -                   denx           mx28
-mx28evk                      arm         arm926ejs   -                   freescale      mx28
+apx4devkit                   arm         arm926ejs   apx4devkit          bluegiga       mxs		apx4devkit
+m28evk                       arm         arm926ejs   m28evk              denx           mxs		m28evk
+mx28evk                      arm         arm926ejs   mx28evk             freescale      mxs		mx28evk
 nhk8815                      arm         arm926ejs   nhk8815             st             nomadik
 nhk8815_onenand              arm         arm926ejs   nhk8815             st             nomadik       nhk8815:BOOT_ONENAND
 omap5912osk                  arm         arm926ejs   -                   ti             omap