esoc: Fix integration with SSR driver

SSR driver expects subsystem descriptor device type to be
struct platform_device, whereas esoc driver is passing a
struct device instead. This results in a NULL pointer crash
during platform_get_irq in subsystem_restart.c. Fix esoc
driver to pass platform_device.

Change-Id: I93d02623cb7ac14ea3171c3792a4c52c73a74dea
Signed-off-by: Arun KS <arunks@codeaurora.org>
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>