NFC: st-nci: Auto-select core module

The core st-nci module is useless without either the I2C or the
SPI access module. So hide NFC_ST_NCI and select it automatically
if either NFC_ST_NCI_I2C or NFC_ST_NCI_SPI is selected.

This avoids presenting NFC_ST_NCI when neither NFC_ST_NCI_I2C nor
NFC_ST_NCI_SPI can be selected.

Cc: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>