dt-bindings: perf: Add DT bindings for LLCC_PMU_VER2 driver

This patch adds the compatible string for the new version of
QCOM LLCC PMU device. Also, modify the compatible string for
version 1 of LLCC PMU to reflect the version numbers clearly.

Change-Id: I6e26daa0bb353d5093c066743dcc1e2f0fc626f1
Signed-off-by: Rama Aparna Mallavarapu <aparnam@codeaurora.org>