refactor(imx8mp): make use of setup_page_tables()

No functional change. Use the setup_page_tables() helper function which
does the three calls for us. Also the function has some logging support
which will be nice during debugging.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Change-Id: I350965414939865220f745ef5b24d2cdc3095e7b

plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c

@@ -198,11 +198,7 @@ void bl31_plat_arch_setup(void)
 		{0}
 	};
 
-	mmap_add(bl_regions);
-	mmap_add(imx_mmap);
-
-	init_xlat_tables();
-
+	setup_page_tables(bl_regions, imx_mmap);
 	enable_mmu_el3(0);
 }