[Blackfin] arch: fix bug - make sure we check the right L1 length

Signed-off-by: Meihui Fan <mhfan@hhcn.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

arch/blackfin/mm/blackfin_sram.c

@@ -401,7 +401,7 @@ EXPORT_SYMBOL(l1_data_sram_free);
 
 void *l1_inst_sram_alloc(size_t size)
 {
-#if L1_DATA_A_LENGTH != 0
+#if L1_CODE_LENGTH != 0
 	unsigned flags;
 	void *addr;