NFC: trf7970a: Fix inaccurate comment in trf7970a_probe()

As of commit ce69b95 ("NFC: Make EN2 pin optional in the
TRF7970A driver"), only the GPIO for the 'EN' enable pin needs
to be specified in the device tree so update the comments that
says both 'EN' and 'EN2' must be specified.

Signed-off-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/trf7970a.c

@@ -2046,7 +2046,7 @@ static int trf7970a_probe(struct spi_device *spi)
 	if (of_property_read_bool(np, "irq-status-read-quirk"))
 		trf->quirks |= TRF7970A_QUIRK_IRQ_STATUS_READ;
 
-	/* There are two enable pins - both must be present */
+	/* There are two enable pins - only EN must be present in the DT */
 	trf->en_gpio = of_get_named_gpio(np, "ti,enable-gpios", 0);
 	if (!gpio_is_valid(trf->en_gpio)) {
 		dev_err(trf->dev, "No EN GPIO property\n");