input: atmel_mxt_ts: Fix config update after firmware upgrade
input: atmel_mxt_ts: Fix config update after firmware upgrade

Following a firmware upgrade on the touch controller, a force config
update is expected. The config update logic is broken as a side effect
of a previous patch. Fix it by properly resetting a cached pointer
after a successful firmware upgrade.

CRs-fixed: 427508
Change-Id: I7ab95cecb6065b2817df653e0f0fde32c6e7636e
Signed-off-by: Jing Lin <c7dcaf15e598b2aa5118eea5524e311c72a36991@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas