s390/smp: use register pair instead of register asm

static __always_inline void set_new_lowcore(struct lowcore *lc)

{

	struct lowcore *old_lc = &S390_lowcore;

	struct lowcore *new_lc = lc;

	union register_pair dst, src;

	u32 pfx;

	register struct lowcore *reg2 asm ("2") = new_lc;

	register unsigned long	 reg3 asm ("3") = sizeof(*reg2);

	register struct lowcore *reg4 asm ("4") = old_lc;

	register unsigned long	 reg5 asm ("5") = sizeof(*reg4);

	src.even = (unsigned long) &S390_lowcore;

	src.odd  = sizeof(S390_lowcore);

	dst.even = (unsigned long) lc;

	dst.odd  = sizeof(*lc);

	pfx = (unsigned long) lc;

	asm volatile(

		"	st	2,%[pfx]\n"

		"	mvcl	2,4\n"

		"	mvcl	%[dst],%[src]\n"

		"	spx	%[pfx]\n"

		: "+&d" (reg2), "+&d" (reg3),

		  "+&d" (reg4), "+&d" (reg5), [pfx] "=Q" (pfx)

		: : "memory", "cc");

		: [dst] "+&d" (dst.pair), [src] "+&d" (src.pair)

		: [pfx] "Q" (pfx)

		: "memory", "cc");

}

static int __init smp_reinit_ipl_cpu(void)