mips: Avoid using config_enabled() directly

Use IS_ENABLED() instead, which is the correct macro for checking a CONFIG
option.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/mips/lib/cache.c b/arch/mips/lib/cache.c
index 51a8f43..ec652f0 100644
--- a/arch/mips/lib/cache.c
+++ b/arch/mips/lib/cache.c
@@ -38,7 +38,7 @@
 			l2c = read_c0_config5() & MIPS_CONF5_L2C;
 	}
 
-	if (l2c && config_enabled(CONFIG_MIPS_CM)) {
+	if (l2c && IS_ENABLED(CONFIG_MIPS_CM)) {
 		gd->arch.l2_line_size = mips_cm_l2_line_size();
 	} else if (l2c) {
 		/* We don't know how to retrieve L2 config on this system */