gdsys: mpc8308: Don't use manual RAM config if RAM driver is active

The "manual" RAM configuration should not be used if the DM RAM driver
is active, hence, disable the code if the CONFIG_MPC83XX_SDRAM config
variable is defined.

Signed-off-by: Mario Six <mario.six@gdsys.cc>

board/gdsys/mpc8308/sdram.c

@@ -11,6 +11,8 @@
  * board\freescale\mpc8315erdb\sdram.c
  */
 
+#ifndef CONFIG_MPC83XX_SDRAM
+
 #include <common.h>
 #include <mpc83xx.h>
 #include <spd_sdram.h>
@@ -81,3 +83,5 @@ int dram_init(void)
 
 	return 0;
 }
+
+#endif /* !CONFIG_MPC83XX_SDRAM */