[Blackfin] arch: fix building with mtd uclinux by putting the mtd_phys option into the function it actually gets used in

Signed-off-by: Mike Frysinger <[e-mail]>
Signed-off-by: Bryan Wu <[e-mail]>

arch/blackfin/kernel/setup.c

···
  */
 static __init void  memory_setup(void)
 {
+#ifdef CONFIG_MTD_UCLINUX
+	unsigned long mtd_phys = 0;
+#endif
+
 	_rambase = (unsigned long)_stext;
 	_ramstart = (unsigned long)_end;
 
···
 void __init setup_arch(char **cmdline_p)
 {
 	unsigned long l1_length, sclk, cclk;
-#ifdef CONFIG_MTD_UCLINUX
-	unsigned long mtd_phys = 0;
-#endif
 
 #ifdef CONFIG_DUMMY_CONSOLE
 	conswitchp = &dummy_con;