Input: drv260x - remove unused defines

Removing some #defines that are not and should never be used pertaining to
I2C.

Removing:
define DRV260X_ALLOWED_R_BYTES	25
define DRV260X_ALLOWED_W_BYTES	2
define DRV260X_MAX_RW_RETRIES	5
define DRV260X_I2C_RETRY_DELAY 10

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>