staging: ks7010: make loading config file optional

We have sane defaults, so we don't need to bail out if there is no
config file. Note that the config file should go away completely in
favour of configuration mechanisms already upstream.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>