ARM: dts: msm: Support download mode through secure I/O on 8916/8939

Add the TCSR_BOOT_MISC_DETECT register address to the
qcom,pshold device on 8916 / 8936 / 8939, to allow
configuring Download Mode / EDL by means of a Secure IO
call rather than a direct SCM call.

Change-Id: Ie2eb9decfdfb855c72bcb784ed29f7d0e8c07beb
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>