s390: remove dead code

Remove some dead code from head64.S, which was left over since commit
da292bbe ("[S390] eliminate ipl_device from lowcore") removed
ipl_device from lowcore.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/head64.S

@@ -27,8 +27,6 @@ ENTRY(startup_continue)
 	mvc	0(16,%r1),__LC_BOOT_CLOCK
 	larl	%r13,.LPG1		# get base
 	lctlg	%c0,%c15,.Lctl-.LPG1(%r13)	# load control registers
-	lg	%r12,.Lparmaddr-.LPG1(%r13)	# pointer to parameter area
-					# move IPL device to lowcore
 	larl	%r0,boot_vdso_data
 	stg	%r0,__LC_VDSO_PER_CPU
 #