1) Add __s390__ to the list of architectures that use unsigned int as
   type for rautofs_wqt_t. __s390__ is defined for both 31-bit and 64-bit
   linux for s/390. Both architectures are fine with unsigned int since
   sizeof(unsigned int) == sizeof(unsigned long) for 31 bit s/390.
2) Remove early initialization call ccwcache_init(). It doesn't exists
   anymore.
3) Remove special case for irq_stat. We moved the irq_stat structure out
   of the lowcore.
4) Replace acquire_console_sem with down_trylock & return to avoid an
   endless trap loop if console_unblank is called from interrupt context
   and the console semaphore is taken.