[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>
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index d3cbfa3..6603fbb 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -45,7 +45,7 @@
 #include <asm/irq.h>
 #include <asm/timer.h>
 
-asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
+asmlinkage void ret_from_fork(void) asm ("ret_from_fork");
 
 /*
  * Return saved PC of a blocked thread. used in kernel/sched.
@@ -177,7 +177,8 @@
 
 extern void kernel_thread_starter(void);
 
-__asm__(".align 4\n"
+asm(
+	".align 4\n"
 	"kernel_thread_starter:\n"
 	"    la    2,0(10)\n"
 	"    basr  14,9\n"