Remove sysfs_remove_bin_file() return-value checking from the areca driver.

There's nothing a driver can do if sysfs file removal fails, so we'll soon be
changing sysfs_remove_bin_file() to internally print a diagnostic and to
return void.

Cc: Erich Chen <erich@areca.com.tw>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>