soc: qcom: Create framework for qcom watchdogs

Separate core watchdog functionality from the qcom watchdog
driver to create a framework for other qcom watchdogs. This
will reduce the duplication of code for future watchdog
drivers and allow them to take advantage of this framework.

Change-Id: I1234af9d92de6841bd09157042a4fbba1745f11b
Signed-off-by: Branden Bonaby <bbonaby@codeaurora.org>