Input: synaptics-rmi4 - remove unneeded variable

Remove the data_base_addr_offset variable in rmi_f11_attention(). The
f11 data is read as a single block so there is no need to store an offset
to the data address.

Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Nick Dyer <nick@shmanahar.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>