efi_loader: GetNextVariableName() relies on REGEX

Our implementation of GetNextVariableName() relies on
CONFIG_REGEX=y. So EFI_LOADER has to select it.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index b921ea8..f5de005 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -8,6 +8,7 @@
 	default y
 	select LIB_UUID
 	select HAVE_BLOCK_DEVICE
+	select REGEX
 	imply CFB_CONSOLE_ANSI
 	help
 	  Select this option if you want to run EFI applications (like grub2)