Input: fix sparse warning in multitouch code
Input: fix sparse warning in multitouch code

This fixes the following sparse warning:
drivers/input/input-mt.c:193:18: warning: Using plain integer as NULL pointer

Signed-off-by: Dmitry Torokhov <6b8646d310837fed93a129ed3c979b90c7f2674f@gmail.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs