lib/Kconfig.debug: add UFS_FAULT_INJECTION config

UFS_FAULT_INJECTION config definition was present on msm-4.4 kernel but
was missed on msm-4.9 while taking snapshot from msm-4.4. Add this config
now so it can be enabled later for debug purposes.

Change-Id: Ia62e30f2f123c0a8c79affb205d1fb956f8f6d57
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>