watchdog: f71808e_wdt: Fix WDTMOUT_STS register read

Tested and verified on Lanner LEC-3030 Industrial PC (with F81865)

Datasheet verified for
 F71808, F71858, F71862, F71869, F71869A, F71882, F71889, F81865

Datasheet references:
F71808A:
 http://www.electronicsdatasheets.com/download/534cf560e34e2406135f4658.pdf?format=pdf
F71858:
 http://www.electronicsdatasheets.com/download/534cf55fe34e2406135f4635.pdf?format=pdf
F71862:
 http://www.hardwaresecrets.com/datasheets/F71862_V027P.pdf
F71869:
 http://www.clubedohardware.com.br/datasheets/366451_F71869.pdf
F71869A:
 http://www.chipset-ic.com/datasheet/F71869AD.pdf
F71882:
 http://www.digchip.com/datasheets/parts/datasheet/931/F71882-pdf.php
F71889:
 http://pdf1.alldatasheet.com/datasheet-pdf/view/406312/FINTEK/F71889.html
F81865:
 http://www.hardwaresecrets.com/datasheets/F81865_V028P.pdf
 http://www.alldatasheet.com/datasheet-pdf/pdf/406317/FINTEK/F81865.html

Signed-off-by: Knud Poulsen <knpo@ieee.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>