mpc85xx: rename sdram_init() lbc_sdram_init()

sdram_init() is used to initialize sdram on the lbc.  Rename it
accordingly.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c
index bea8e10..afa9ca9 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu.c
@@ -331,7 +331,7 @@
 #endif
 
 	/* Some boards also have sdram on the lbc */
-	sdram_init();
+	lbc_sdram_init();
 
 	puts("DDR: ");
 	return dram_size;