ARM: dts: msm: refactor smb1351 node to top level msm8996-mtp

In msm8996-v1 smb1357 is used as the parallel charger solution,
and subsequent versions of msm8996 use smb1351.

Since msm8996-v1 support has been dropped from the device tree,
refactor the smb1351 node to the top level msm8996-mtp.

Change-Id: I5ff852e890c0294a44cc8c9bbcc26b4eb34e6f4e
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>