power: smb5-lib: Add DT option to disable LPD feature

Currently, the Liquid Presence Detection feature is enabled by default
on USB Type-C port. However, it may not be desired on some platforms
that share this driver.

Provide a DT option to switch LPD feature off.

This patch has been updated to reduce the cyclomatic complexity of
smb5_init_hw().

Change-Id: I5c08e9fe8bd1bdc569de8dafdd5f3616edadb629
Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>