lockup-watchdogs: Fix a typo

s/BOOTPARAM_HARDLOCKUP_PANIC/BOOTPARAM_SOFTLOCKUP_PANIC

Signed-off-by: Harish Jenny K N <harish_kandiga@mentor.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>