soc: qcom: bgcom_dev: handle ssr events for Blackghost and Modem

Register to SSR framework for BG and Modem. Transfer uevents from
kernel space to user space. Add bgcom spi free and busy functionality.

Change-Id: Iff49efc87f402f28fc39fff1c42d22271677fb2b
Signed-off-by: Pranshu Gupta <pransh@codeaurora.org>
Signed-off-by: Bikshapathi Kothapeta <bkotha@codeaurora.org>