Input: Add enabled device attribute

Allows closing the hardware device while the input device is open.

cherry-picking from android-exynos-manta-3.4-jb-mr1.1
commit id 8da9e5fe1e25de1cb9ab8d2d74f4d7fff8d7a220

Change-Id: I91b6e24f14b3334d17bfe8e5f86d2b33c85e1ea1
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Input: Set users to 0 when an input device is disabled though sysfs

Some drivers check dev->users suspend and resume. If the device
was turned off with the sysfs hook, it should not turn back on
in resume.

cherry-picking from android-exynos-manta-3.4-jb-mr1.1
commit id ebdfb336782deafee6667730c1ca1b3c1fbd551e

Change-Id: Iff17fdac307ec9c27744ac886f9dc94aac665c80
Signed-off-by: Arve Hjønnevåg <arve@android.com>