MIPS: DEC: use IS_ENABLED()

Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3333/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/dec/prom/memory.c

@@ -101,7 +101,7 @@ void __init prom_free_prom_memory(void)
 	 * the first page reserved for the exception handlers.
 	 */
 
-#if defined(CONFIG_DECLANCE) || defined(CONFIG_DECLANCE_MODULE)
+#if IS_ENABLED(CONFIG_DECLANCE)
 	/*
 	 * Leave 128 KB reserved for Lance memory for
 	 * IOASIC DECstations.