Fix "can not" in Documentation and Kconfig

Randy brought it to my attention that in proper english "can not" should always
be written "cannot". I donot see any reason to argue, even if I mightnot
understand why this rule exists.  This patch fixes "can not" in several
Documentation files as well as three Kconfigs.

Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

Documentation/watchdog/watchdog-api.txt

@@ -258,13 +258,13 @@ booke_wdt.c -- PowerPC BookE Watchdog Timer
 	Timeout default varies according to frequency, supports
 	SETTIMEOUT
 
-	Watchdog can not be turned off, CONFIG_WATCHDOG_NOWAYOUT
+	Watchdog cannot be turned off, CONFIG_WATCHDOG_NOWAYOUT
 	does not make sense
 
 	GETSUPPORT returns the watchdog_info struct, and
 	GETSTATUS returns the supported options. GETBOOTSTATUS
 	returns a 1 if the last reset was caused by the
-	watchdog and a 0 otherwise. This watchdog can not be
+	watchdog and a 0 otherwise. This watchdog cannot be
 	disabled once it has been started. The wdt_period kernel
 	parameter selects which bit of the time base changing
 	from 0->1 will trigger the watchdog exception. Changing