Revert "i2c: at91: Read all available bytes at once"

This reverts commit e8f39e9.

This commit makes linux go in infinite loop inside IRQ context
if any i2c device is stuck.
Linux will keep receiving RXRDY. So this is not a good way to handle
reading from the controller

Author: ehristev

drivers/i2c/busses/i2c-at91.c

@@ -518,16 +518,8 @@ static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
 	 * the RXRDY interrupt first in order to not keep garbage data in the
 	 * Receive Holding Register for the next transfer.
 	 */
-	if (irqstatus & AT91_TWI_RXRDY) {
-		/*
-		 * Read all available bytes at once by polling RXRDY usable w/
-		 * and w/o FIFO. With FIFO enabled we could also read RXFL and
-		 * avoid polling RXRDY.
-		 */
-		do {
-			at91_twi_read_next_byte(dev);
-		} while (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY);
-	}
+	if (irqstatus & AT91_TWI_RXRDY)
+		at91_twi_read_next_byte(dev);
 
 	/*
 	 * When a NACK condition is detected, the I2C controller sets the NACK,