boards: fix Makefile.dep indentation

boards/cc2538dk/Makefile.dep

 ifneq (,$(filter gnrc_netdev_default,$(USEMODULE)))
-    USEMODULE += netif
-    USEMODULE += cc2538_rf
-    USEMODULE += gnrc_netdev
-    USEMODULE += netdev_ieee802154
+  USEMODULE += netif
+  USEMODULE += cc2538_rf
+  USEMODULE += gnrc_netdev
+  USEMODULE += netdev_ieee802154
 endif

boards/native/Makefile.dep

 ifneq (,$(filter netdev_default gnrc_netdev_default,$(USEMODULE)))
-    USEMODULE += netdev_tap
+  USEMODULE += netdev_tap
 endif
 
 ifneq (,$(filter mtd,$(USEMODULE)))
-    USEMODULE += mtd_native
+  USEMODULE += mtd_native
 endif
 
 ifneq (,$(filter can,$(USEMODULE)))
-    ifeq ($(shell uname -s),Linux)
-        USEMODULE += can_linux
-        CFLAGS += -DCAN_DLL_NUMOF=2
-    endif
+  ifeq ($(shell uname -s),Linux)
+    USEMODULE += can_linux
+    CFLAGS += -DCAN_DLL_NUMOF=2
+  endif
 endif

boards/openmote-cc2538/Makefile.dep

 ifneq (,$(filter gnrc_netdev_default,$(USEMODULE)))
-    USEMODULE += netif
-    USEMODULE += cc2538_rf
-    USEMODULE += gnrc_netdev
-    USEMODULE += netdev_ieee802154
+  USEMODULE += netif
+  USEMODULE += cc2538_rf
+  USEMODULE += gnrc_netdev
+  USEMODULE += netdev_ieee802154
 endif

boards/remote-common/Makefile.dep

 ifneq (,$(filter gnrc_netdev_default,$(USEMODULE)))
-    USEMODULE += netif
-    USEMODULE += cc2538_rf
-    USEMODULE += gnrc_netdev
-    USEMODULE += netdev_ieee802154
+  USEMODULE += netif
+  USEMODULE += cc2538_rf
+  USEMODULE += gnrc_netdev
+  USEMODULE += netdev_ieee802154
 endif
 
 ifneq (,$(filter saul_default,$(USEMODULE)))