arm: fix the compilation error with trigger backtrace call

arch_trigger_all_cpu_backtrace() takes a boolean on arm
platforms. So, the trigger_all_cpu_backtrace() in nmi.h
results in compilation error. Fix it.

Change-Id: I9a1045333115ab1726f85e360ef0e302486341c4
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>
[jshriram: Fix trivial merge conflicts]
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>