mmc: cmdq_hci: Fix memcpy buffer overflow in cmdq task history

This patch fixes the buffer overflow in memcpy while logging cmdq
task history. Cmdq task history used only for debugging purpose.

Change-Id: Ia2f70e0f4316f7f55e4b96aac5da54e8dcd7e435
Signed-off-by: Ram Prakash Gupta <rampraka@codeaurora.org>