staging: rts5208: Rewrite redundant if statement to improve code style

This commit uses the fact that

    if (a) {
            if (b) {
                    ...
            }
    }

can instead be written as

    if (a && b) {
            ...
    }

without any change in behavior, allowing to decrease the indentation
of the contained code block and thus reducing the average line length.

Signed-off-by: Tobias Nießen <tobias.niessen@stud.uni-hannover.de>
Signed-off-by: Sabrina Gaube <sabrina-gaube@web.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>