platform: qpnp-revid: add support to identify PMI8937

PMI8937 has same subtype as PMI8950 and is identified by
SPARE0, add support to detect PMI8937.
Add the name 'PMI8937' to the list of pmic names.

Change-Id: I1f36cb8648f4970c0281aede0119b03e37a89927
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>