staging: iio: tsl2x7x: bugfixes

TAOS (version 9a) tsl2x7x driver change / bug fix.

Fixed - removed decimal multiplications.
        Added missing 'static' declarations
        Fixed _read_raw case logic to allow reading of _PROCESSED IIO_LIGHT
	Replaced udelay with mdelay to accomodate eabi.

Signed-off-by: Jon Brenner <jbrenner@taosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>