misc: fastrpc: Rename tgid and pid to client_id

misc: fastrpc: Rename tgid and pid to client_id

The information passed as request tgid and pid is actually the
client id of the process. This client id is used as an
identifier by DSP to identify the DSP PD corresponding to the
process. Currently process tgid is getting passed as the
identifier which is getting replaced by a custom client id.
Rename the data which uses this client id.

Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20250110134308.123739-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>