powerpc/85xx: Declare fsl_ddr_set_memctl_regs in <asm/fsl_ddr_sdram.h>

Remove declerations of fsl_ddr_set_memctl_regs in board files with and
place it into a common header.

Based on patch from Poonam Aggrwal.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/fsl_ddr_sdram.h b/arch/powerpc/include/asm/fsl_ddr_sdram.h
index 02a1f5d..b5b1efe 100644
--- a/arch/powerpc/include/asm/fsl_ddr_sdram.h
+++ b/arch/powerpc/include/asm/fsl_ddr_sdram.h
@@ -271,6 +271,8 @@
 
 extern phys_size_t fsl_ddr_sdram(void);
 extern int fsl_use_spd(void);
+extern void fsl_ddr_set_memctl_regs(const fsl_ddr_cfg_regs_t *regs,
+					unsigned int ctrl_num);
 
 /*
  * The 85xx boards have a common prototype for fixed_sdram so put the