[S390] Inline assembly cleanup.

Major cleanup of all s390 inline assemblies. They now have a common
coding style. Quite a few have been shortened, mainly by using register
asm variables. Use of the EX_TABLE macro helps  as well. The atomic ops,
bit ops and locking inlines new use the Q-constraint if a newer gcc
is used.  That results in slightly better code.

Thanks to Christian Borntraeger for proof reading the changes.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

include/asm-s390/smp.h

@@ -56,7 +56,7 @@ static inline __u16 hard_smp_processor_id(void)
 {
         __u16 cpu_address;
  
-        __asm__ ("stap %0\n" : "=m" (cpu_address));
+	asm volatile("stap %0" : "=m" (cpu_address));
         return cpu_address;
 }