arm64: remove unneeded copy to init_utsname()->machine

As you see in init/version.c, init_uts_ns.name.machine is initially
set to UTS_MACHINE.  There is no point to copy the same string.

I dug the git history to figure out why this line is here.  My best
guess is like this:

 - This line has been around here since the initial support of arm64
   by commit 9703d9d7 ("arm64: Kernel booting and initialisation").
   If ARCH (=arm64) and UTS_MACHINE (=aarch64) do not match,
   arch/$(ARCH)/Makefile is supposed to override UTS_MACHINE, but the
   initial version of arch/arm64/Makefile missed to do that.  Instead,
   the boot code copied "aarch64" to init_utsname()->machine.

 - Commit 94ed1f2c ("arm64: setup: report ELF_PLATFORM as the
   machine for utsname") replaced "aarch64" with ELF_PLATFORM to
   make "uname" to reflect the endianness.

 - ELF_PLATFORM does not help to provide the UTS machine name to rpm
   target, so commit cfa88c79 ("arm64: Set UTS_MACHINE in the
   Makefile") fixed it.  The commit simply replaced ELF_PLATFORM with
   UTS_MACHINE, but missed the fact the string copy itself is no longer
   needed.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/Makefile

@@ -10,8 +10,6 @@ CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg
 
-CFLAGS_setup.o = -DUTS_MACHINE='"$(UTS_MACHINE)"'
-
 # Object file lists.
 arm64-obj-y		:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   entry-fpsimd.o process.o ptrace.o setup.o signal.o	\

arch/arm64/kernel/setup.c

@@ -23,7 +23,6 @@
 #include <linux/stddef.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
-#include <linux/utsname.h>
 #include <linux/initrd.h>
 #include <linux/console.h>
 #include <linux/cache.h>
@@ -246,7 +245,6 @@ void __init setup_arch(char **cmdline_p)
 {
 	pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
 
-	sprintf(init_utsname()->machine, UTS_MACHINE);
 	init_mm.start_code = (unsigned long) _text;
 	init_mm.end_code   = (unsigned long) _etext;
 	init_mm.end_data   = (unsigned long) _edata;