x86: fix UML and -regparm=3

introduce the "asmregparm" calling convention: for functions
implemented in assembly with a fixed regparm input parameters
calling convention.

mark the semaphore and rwsem slowpath functions with that.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/linkage.h

@@ -13,6 +13,10 @@
 #define asmlinkage CPP_ASMLINKAGE
 #endif
 
+#ifndef asmregparm
+# define asmregparm
+#endif
+
 #ifndef prevent_tail_call
 # define prevent_tail_call(ret) do { } while (0)
 #endif