m68knommu: enumerate INIT_THREAD fields properly

Use proper field value setting init INIT_THREAD macro.
Fixes this:

arch/m68knommu/kernel/init_task.c:27: warning: excess elements in array initializer
arch/m68knommu/kernel/init_task.c:27: warning: (near initialization for ‘init_task.thread.fpstate’)

Signed-off-by: Greg Ungerer <gerg@uclinux.org>