avtimer: msm: allow driver to register to SSR framework

Sub System Restart[SSR] framework allows driver to handle
unexpected crash in middle of operation.
Also, adding support clk_div dtsi entry to calculate
avtimer_lsw value.

CRs-Fixed: 689849
Change-Id: I521e3c010dadd00a06a0fe8998a1759b2eb81b55
Signed-off-by: Laxminath Kasam <lkasam@codeaurora.org>