HSD #14015013554: firmware: stratix10-svc: Support up to 4 SVC clients

commit c96097ae029fd6a606ef8023cd14d70f2d712d48 from
https://github.com/altera-opensource/linux-socfpga.git

 socfpga-5.15.30-lts.

This fixes the SVC Time-out issue on Intel's firmware SVC mailbox service
when more than 1 client driver sends SMC commands concurrently. A thread
is created now per channel. Current stratix10-svc driver supports 4
channels. Thread synchronization with mutex is used to prevent more
than one thread from calling SMC command. The time-out are adjusted
to cater for multiple drivers.

In the old implementation, the respective SVC client drivers like
soc64-hwmon, intel_fcs and stratix10-soc sends a SMC command
and this triggers a single thread at the stratix10-svc driver.
Upon receiving a callback, the caller driver sends
stratix10-svc-done and it stops the thread without waiting
for the other SMC commands to complete.

Signed-off-by: Ang Tien Sung <tien.sung.ang@intel.com>
Signed-off-by: Liwei Song <liwei.song@windriver.com>