Input: psmouse - clean up Cypress probe

When Cypress protocol support is disabled cypress_init() is a stub that
always returns -ENOSYS, so there is not point in testing for
CONFIG_MOUSE_PS2_CYPRESS after we decided that we are dealing with a
Cypress device. Also, we should only be calling cypress_detect() when
set_properties argument is "true", like with other protocols.

There is a slight change in behavior to make follow-up patches more
uniform: when we detect Cypress but its initialization fails, instead of
immediately returning PSMOUSE_PS2 protocol we now continue trying
IntelliMouse [Explorer]. Given that Cypress devices only have issue with
Sentelic probes probing Imtellimouse should be safe.

Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Marcin Sochacki <msochacki+kernel@gmail.com>
Tested-by: Till <till2.schaefer@uni-dortmund.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>