BACKPORT:FROMGIT: coresight: funnel: Fix missing spin_lock_init()

Backport: context code is different from upstream.

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

This is detected by Coccinelle semantic patch.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Tested-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

(cherry picked from commit 9d5ec2ec787967f16598094de507a60816378fae
 https://git.linaro.org/kernel/coresight.git

 next)

Bug: 140266694
Change-Id: I34da2da267afa839d7432bd7c33bcf92d6287ef0
Signed-off-by: Yabin Cui <yabinc@google.com>