ppc: Cleanup get_effective_memsize() use

Removed duplicated effective memory size calculation code.
Signed-off-by: NMarian Balakowicz <m8@semihalf.com>

lib_ppc/board.c

@@ -453,18 +453,7 @@ void board_init_f (ulong bootflag)
 	 */
 	gd->ram_size -= CFG_MEM_TOP_HIDE;
 
-#ifndef CONFIG_MAX_MEM_MAPPED
-#define CONFIG_MAX_MEM_MAPPED (256 << 20)
-#endif
-
-#ifndef	CONFIG_VERY_BIG_RAM
 	addr = CFG_SDRAM_BASE + get_effective_memsize();
-#else
-	/* only allow stack below 256M */
-	addr = CFG_SDRAM_BASE +
-		(gd->ram_size > CONFIG_MAX_MEM_MAPPED) ?
-		CONFIG_MAX_MEM_MAPPED : get_effective_memsize();
-#endif
 
 #ifdef CONFIG_LOGBUFFER
 #ifndef CONFIG_ALT_LB_ADDR