NFC: nfcsim: Fix missing dependency on NFC_DIGITAL

The nfcsim driver now depends on the Digital layer. This patch adds the
missing dependency on NFC_DIGITAL for NFC_SIM config.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/nfc/Kconfig b/drivers/nfc/Kconfig
index ea8321a..9d23692 100644
--- a/drivers/nfc/Kconfig
+++ b/drivers/nfc/Kconfig
@@ -40,6 +40,7 @@
 
 config NFC_SIM
 	tristate "NFC hardware simulator driver"
+	depends on NFC_DIGITAL
 	help
 	  This driver declares two virtual NFC devices supporting NFC-DEP
 	  protocol. An LLCP connection can be established between them and