soc: spcom: Pass channel name as formatted string to device_create

Pass channel name as formmated string to device_create call in
spcom_create_channel_chardevto prevent memory access issues when
using formatted string as channel name.

Change-Id: I549087a49e97f0b1a66ea5816eabfe80a6f7f1f7
Signed-off-by: Liron Daniel <lirond@codeaurora.org>
Signed-off-by: Liron Daniel <quic_lirond@quicinc.com>