Further renames of platform porting functions

Rename the ic_* platform porting functions to plat_ic_* to be
consistent with the other functions in platform.h. Also rename
bl31_get_next_image_info() to bl31_plat_get_next_image_ep_info()
and remove the duplicate declaration in bl31.h.

Change-Id: I4851842069d3cff14c0a468daacc0a891a7ede84
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index 71c6464..5117793 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -165,7 +165,7 @@
 	bl31_next_el_arch_setup(image_type);
 
 	/* Program EL3 registers to enable entry into the next EL */
-	next_image_info = bl31_get_next_image_info(image_type);
+	next_image_info = bl31_plat_get_next_image_ep_info(image_type);
 	assert(next_image_info);
 
 	scr = read_scr();