update message for disabling runtime cpu detection

aom_ports/arm_cpudetect.c

diff --git a/aom_ports/arm_cpudetect.c b/aom_ports/arm_cpudetect.c
index c5c9f48..7d66746 100644
--- a/aom_ports/arm_cpudetect.c
+++ b/aom_ports/arm_cpudetect.c
@@ -146,6 +146,6 @@
 }
 #else  /* end __linux__ */
 #error \
-    "--enable-runtime-cpu-detect selected, but no CPU detection method " \
-"available for your platform. Reconfigure with --disable-runtime-cpu-detect."
+    "-DCONFIG_RUNTIME_CPU_DETECT=1 selected, but no CPU detection method " \
+"available for your platform. Reconfigure with -DCONFIG_RUNTIME_CPU_DETECT=0"
 #endif