diag: Fix to support separate packet stream for UART MODE

In UART logging MODE diag driver does not separate the packet
for local and remote processor. This change adds support to
separate packet stream for local and remote processor.

CRs-Fixed: 414140
Change-Id: I735d0fb9b85653d11249a310cf9e72ce886ed91f
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>