OMAP3:SDRC: introduce DDR types

Micron DDR timings based on:
http://www.sakoman.net/cgi-bin/gitweb.cgi?p=x-load-omap3.git;a=blob;f=include/asm/arch-omap3/mem.h;h=e6fbfe3947f5d0d85fea776e30821d4017316d86;hb=HEAD

Introduce Micron DDR timings and provide
CONFIG_OMAP3_INFINEON_DDR and CONFIG_OMAP3_MICRON_DDR config
options to allow for platform files to setup their timings as
per the type of DDR selected

Reported-by: Steve Sakoman in http://www.nabble.com/forum/Permalink.jtp?root=25779518&post=25959734&page=y

Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/include/configs/omap3_overo.h b/include/configs/omap3_overo.h
index ffb515d..0f812a7 100644
--- a/include/configs/omap3_overo.h
+++ b/include/configs/omap3_overo.h
@@ -89,6 +89,9 @@
 #define CONFIG_OMAP3_MMC		1
 #define CONFIG_DOS_PARTITION		1
 
+/* DDR - I use Micron DDR */
+#define CONFIG_OMAP3_MICRON_DDR		1
+
 /* commands to include */
 #include <config_cmd_default.h>