arm64: Set UTS_MACHINE in the Makefile

The make rpm target depends on proper UTS_MACHINE definition.  Also, use
the variable in arch/arm64/kernel/setup.c, so that it's not accidentally
removed in the future.
Reported-and-tested-by: Fabian Vogt <fvogt@suse.com>
Signed-off-by: Michal Marek <mmarek@suse.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/Makefile

@@ -46,10 +46,12 @@ ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 AS		+= -EB
 LD		+= -EB
+UTS_MACHINE	:= aarch64_be
 else
 KBUILD_CPPFLAGS	+= -mlittle-endian
 AS		+= -EL
 LD		+= -EL
+UTS_MACHINE	:= aarch64
 endif
 
 CHECKFLAGS	+= -D__aarch64__

arch/arm64/kernel/Makefile

@@ -10,6 +10,8 @@ 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

@@ -233,7 +233,7 @@ void __init setup_arch(char **cmdline_p)
 {
 	pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
 
-	sprintf(init_utsname()->machine, ELF_PLATFORM);
+	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;