staging/easycap: prefer printk over SAY in module entry functions

Use INFO level when registering driver and ERR for error.
Drop messages from oneliner exit function

Cc: Mike Thomas <rmthomas@sciolus.org>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>