i2c: omap: simplify num_bytes handling

trivial patch, no functional changes

If the fifo is disabled or fifo_size is 0 the num_bytes
is set to 1. Else it is set to fifo_size or in case of a
draining interrupt the remaining bytes in the buff stat.
So the zero check is redundant and can be safely optimised.
Signed-off-by: NFelipe Balbi <balbi@ti.com>
Reviewed-by : Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: NShubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

drivers/i2c/busses/i2c-omap.c

@@ -812,8 +812,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
 							OMAP_I2C_BUFSTAT_REG)
 							>> 8) & 0x3F;
 			}
-			while (num_bytes) {
-				num_bytes--;
+			while (num_bytes--) {
 				w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 				if (dev->buf_len) {
 					*dev->buf++ = w;
@@ -855,8 +854,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
 							OMAP_I2C_BUFSTAT_REG)
 							& 0x3F;
 			}
-			while (num_bytes) {
-				num_bytes--;
+			while (num_bytes--) {
 				w = 0;
 				if (dev->buf_len) {
 					w = *dev->buf++;