kconfig: remove unneeded dependency on !SPL_BUILD

Now CONFIG_SPL_BUILD is not defined in Kconfig, so
"!depends on SPL_BUILD" and "if !SPL_BUILD" are redundant.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/scripts/Makefile.uncmd_spl b/scripts/Makefile.uncmd_spl
index 86c938e..343c3fc 100644
--- a/scripts/Makefile.uncmd_spl
+++ b/scripts/Makefile.uncmd_spl
@@ -13,4 +13,6 @@
 CONFIG_DM_SPI_FLASH=
 endif
 
+CONFIG_DM_DEVICE_REMOVE=
+
 endif