soc: qcom: scm_qcpe: Fix support to scm_call2_atomic

The implementation of scm_call2_atomic must be atomic safe, since
clients may call it from an atomic context.

Fix calls to HAB APIs such that:

- The habmm_socket_open() API is called in init time, which is not an
  atomic context.
- If scm_call2_atomic() is used, call an atomic-safe version of the
  habmm_socket_send() & habmm_socket_receive() APIs.

Change-Id: I96fc8fe5142b83013cb7c6d31fed0598ed3dce95
Signed-off-by: Amit Blay <ablay@codeaurora.org>