make: fix build failure on macos with GNU make <= 3.81

Closes https://github.com/espressif/esp-idf/issues/3459

components/soc/component.mk

@@ -1,6 +1,6 @@
 SOC_NAME := $(IDF_TARGET)
 
-COMPONENT_SRCDIRS := $(SOC_NAME) src/ src/hal
+COMPONENT_SRCDIRS := $(SOC_NAME) src src/hal
 
 COMPONENT_ADD_INCLUDEDIRS := $(SOC_NAME)/include include