USB: mos7840: correct handling of CS5 setting

This patch removes an erroneous check of CSIZE, which made it impossible to set
CS5.

Compiles clean, but couldn't test against hardware.

Signed-off-by: Colin Leitner <colin.leitner@gmail.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>