qcom: sysmon: Replace statically allocating sysmon subsys information

Dynamically allocate sysmon_subsys structures instead of relying
on static information.

Change-Id: I6ce78773697c8c1f9fab811bcda6a1aecb520c2e
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>