staging: fbtft: Don't spam logs when probe is deferred

staging: fbtft: Don't spam logs when probe is deferred

When requesting GPIO line the probe can be deferred.
In such case don't spam logs with an error message.
This can be achieved by switching to dev_err_probe().

Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>