[WATCHDOG] v2.6.6 sc520_wdt.c-patch1

Clean-up (general stuff: comments, keep module parameters together, ...)
Added clear definitions for the Watchdog Timer Control Register bits
Made start, stop and keepalive return 0 if successful
Fixed nowayout behaviour so that it is consistent with other watchdog drivers
Fixed release behaviour so that it is consistent with other watchdog drivers
Added wdt_set_heartbeat function to set the timeout/heartbeat of the watchdog
Made sure that memory remapping (wdtmrctl) is done before misc_register is started
MMCR_BASE_DEFAULT was wrong (Bug 2497 reported by Sean Young)

Tested by Sean Young