refactor(plat/imx/imx): make imx io-storage logic for TBBR/FIP common

This commit makes imx image io-storage logic common for all
imx platform.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
Change-Id: I15045ac8f9dfa8cb714e32f9e7475d5eae4e86e4
diff --git a/plat/imx/imx8m/imx8mm/include/imx8mm_private.h b/plat/imx/imx8m/imx8mm/include/imx8mm_private.h
index 52d13f0..5e0ef97 100644
--- a/plat/imx/imx8m/imx8mm/include/imx8mm_private.h
+++ b/plat/imx/imx8m/imx8mm/include/imx8mm_private.h
@@ -10,6 +10,6 @@
 /*******************************************************************************
  * Function and variable prototypes
  ******************************************************************************/
-void plat_imx8mm_io_setup(void);
+void plat_imx_io_setup(void);
 
 #endif /* IMX8MM_PRIVATE_H */