i2c-comcerto: dev_warn -> dev_printk(KERN_DEBUG

i2c-comcerto used dev_warn() from interrupt context. This turned out to
be problematic because dev_warn() won't return until the message has
been sent out on the serial console.
To avoid this issue, we use dev_printk(KERN_DEBUG,...). Messages marked
with KERN_DEBUG will be available through dmesg but won't be printed to
the console.

Change-Id: I47c5d38bea3016eabe884541524c51476283560f
1 file changed