ARM: dts: Update property node for qcom,vctl-timeout-us

The vctl property was incorrectly documented as qcom,saw2-vctl-timeout-us.
Update the documentation with the expected property name.

Change-Id: I477cf06e86a0074d1546d7eddf700a9bc26c645c
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>