Currently the valid variable is of type char, but it is used as boolean.
So let's change it to bool.
Signed-off-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
[groeck: Update description]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>