input: touchscreen: ft5x06: fix firmware force update issue

Force firmware update cannot work when touchscreen controller
cannot report correct family ID. If touchscreen is does not work
in correct state and it reports wrong family ID, it cannot be
recovered by force update, this change use family ID from device
tree instead of read from controller register to fix this issue.

  This patch is propagated from 3.10 kernel
    commit: 69a3ecf0635f5990cab050c4ff4b576f6ecb241f
    input: touchscreen: ft5x06: fix firmware force update issue

Change-Id: I85d24bfc68a7777053c15f28a84027260c68cebd
Signed-off-by: Bingzhe Cai <bingzhec@codeaurora.org>