staging: vc04_services: use 'time_left' variable with wait_for_completion_timeout()

staging: vc04_services: use 'time_left' variable with wait_for_completion_timeout()

There is a confusing pattern in the kernel to use a variable named
'timeout' to store the result of wait_for_completion_timeout() causing
patterns like:

        timeout = wait_for_completion_timeout(...)
        if (!timeout) return -ETIMEDOUT;

with all kinds of permutations. Use 'time_left' as a variable to make the
code self explaining.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240620182538.5497-2-wsa+renesas@sang-engineering.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>