drivers: soc: qcom: rimps_log: remove unused character while printing

Discard character printing in ipc log buf when get_next_logbuf()
returns count value less than the size argument.

Change-Id: I0ba388400c76c16da423a2ccb67d961ed31e87b4
Signed-off-by: Santosh Mardi <gsantosh@codeaurora.org>