saa7164: remove unused saa7164_call_i2c_clients declaration

saa7164_call_i2c_clients has been removed in media/video since
commit 5a6fa3fe ("[media] saa7164: Remove unused
saa7164_call_i2c_clients()").

Then media/video has beed renamed media/pci since
commit b285192a ("[media] rename most media/video pci
drivers to media/pci").

So saa7164_call_i2c_clients is a unused declaration, remove it.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>