perf: avoid picking up a dependency on libunwind

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/devel/perf/Makefile

@@ -51,6 +51,7 @@ MAKE_FLAGS = \
 	NO_GTK2=1 \
 	NO_LIBAUDIT=1 \
 	NO_LIBCRYPTO=1 \
+	NO_LIBUNWIND=1 \
 	CROSS_COMPILE="$(TARGET_CROSS)" \
 	CC="$(TARGET_CC)" \
 	LD="$(TARGET_CROSS)ld" \