lib/mpi: checks for zero divisor length
lib/mpi: checks for zero divisor length

Divisor length should not be 0.

Signed-off-by: Dmitry Kasatkin <8adb5f95ce8fa26dbddb33bd46c9f98f39d4d75f@intel.com>
Reviewed-by: Tetsuo Handa <3d00b54ad717112934d0b63b7ac2975b44022a61@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <10d11de3abc355eabe955bb734f0f8e71da56e16@namei.org>

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