dell_rbu: Select CONFIG_FW_LOADER_USER_HELPER explicitly

The usermode helper is mandatory for this driver.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 9387630..0747872 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -64,6 +64,7 @@
 	tristate "BIOS update support for DELL systems via sysfs"
 	depends on X86
 	select FW_LOADER
+	select FW_LOADER_USER_HELPER
 	help
 	 Say m if you want to have the option of updating the BIOS for your
 	 DELL system. Note you need a Dell OpenManage or Dell Update package (DUP)