Input: sentelic - filter taps in absolute mode

Taps in absolute positioning single-finger mode are currently reported
as physical clicks by the driver. This should be handled by userspace,
not the kernel.

When a tap occurs, the FSP_PB0_LBTN bit is set, but the FSP_PB0_PHY_BTN
is not. We use this to filter out physical clicks from taps.

Signed-off-by: Oskari Saarenmaa <os@ohmu.fi>
Reviewed-by: Tai-hwa Liang <avatar@sentelic.com>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>