dectmngr: Do not install DCX81 firmware for Airoha platform

- Update the makefile
- Remove the .bin file for Airoha

dectmngr/Makefile

@@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=dectmngr
 PKG_RELEASE:=3
-PKG_VERSION:=3.7.3
+PKG_VERSION:=3.7.4
 
 LOCAL_DEV=0
 ifneq ($(LOCAL_DEV),1)
@@ -61,9 +61,7 @@ define Package/$(PKG_NAME)/install
 
 	$(INSTALL_BIN) $(PKG_BUILD_DIR)/app/dectmngr $(1)/usr/sbin/
 	$(STRIP) $(1)/usr/sbin/dectmngr
-ifneq ($(CONFIG_TARGET_airoha),)
-	$(CP) ./firmware/airoha/* $(1)/etc/dspg/
-else
+ifeq ($(CONFIG_TARGET_airoha),)
 	$(CP) ./firmware/common/* $(1)/etc/dspg/
 endif
 	$(CP) ./files/etc/* $(1)/etc/