powerpc/64e: Simplify address calculation in secondary hold loop

As the earlier comment explains, __secondary_hold_spinloop does not have
to be accessed at its virtual address, slightly simplifying code.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230203113858.1152093-4-npiggin@gmail.com

arch/powerpc/kernel/head_64.S

@@ -160,12 +160,8 @@ __secondary_hold:
 	std	r24,(ABS_ADDR(__secondary_hold_acknowledge, first_256B))(0)
 	sync
 
-	li	r26,0
-#ifdef CONFIG_PPC_BOOK3E_64
-	tovirt(r26,r26)
-#endif
 	/* All secondary cpus wait here until told to start. */
-100:	ld	r12,(ABS_ADDR(__secondary_hold_spinloop, first_256B))(r26)
+100:	ld	r12,(ABS_ADDR(__secondary_hold_spinloop, first_256B))(0)
 	cmpdi	0,r12,0
 	beq	100b