Do not reset the TouchpadInputMapper when not needed

Currently TouchpadInputMapper's reset() is always called when
updating the enable state of the device even if a requested state is
already matched.
It causes unexpected reset when a cursor crosses a display boundary.

Bug: 429067963
Test: inputflinger_tests
Flag: EXEMPT small bug fix
Change-Id: Ifa14a7417d3afc7f02d929ec1c0b328b1b74aee5