NFC: IRQ gpio usage modification in nfc_read

Modified condition to ensure data is read
only after interrupt has occurred.

Spurious interrupt handling is done in nfc_read
instead of irq handler.

Change-Id: Ie2362610fe922e792e6358b4386c828fdd754fa8
Signed-off-by: Gaurav Singhal <gsinghal@codeaurora.org>