arm: omap: rename board-rx51-sdram.c to sdram-nokia.c

Rename the file and functions so that it can be reused by future Nokia
boards. Based on patches by Juha Keski-Saari.

Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 60e51bc..e72ccf7 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -140,7 +140,7 @@
 					   board-flash.o
 obj-$(CONFIG_MACH_NOKIA_N8X0)		+= board-n8x0.o
 obj-$(CONFIG_MACH_NOKIA_RX51)		+= board-rx51.o \
-					   board-rx51-sdram.o \
+					   sdram-nokia.o \
 					   board-rx51-peripherals.o \
 					   board-rx51-video.o \
 					   hsmmc.o