qcom/watchdog_v2: Disable watchdog before booting crash kernel

While booting capture kernel non-secure watchdog bite is fired. This
happens as in panic path before disabling watchdog crash_kexec()
starts booting crash kernel.
Disable watchdog before going into crash_kexec() for booting crash
kernel.

Change-Id: Ic27a5e36acdf24f132447257c5a73eb546ca55ac
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Akshay Adiga <aadiga@codeaurora.org>