Input: elan_i2c - fix firmware update on newer ICs

The argument to iap page type command depends on the firmware page size.

Fixes: bfd9b92b

 ("Input: elan_i2c - handle firmware updated on newer ICs")
Signed-off-by: Jingle Wu <jingle.wu@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>