linux_user: elfload: Default ELF_MACHINE to ELF_ARCH

In most (but not all) cases, ELF_MACHINE and ELF_ARCH are safely the
same. Default ELF_MACHINE to ELF_ARCH. This makes defining ELF_MACHINE
optional for target-*/cpu.h when they are known to match.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Acked-By: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

linux-user/elfload.c

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 39f3282..4ed8c5e 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1245,6 +1245,10 @@
 #define ELF_PLATFORM (NULL)
 #endif
 
+#ifndef ELF_MACHINE
+#define ELF_MACHINE ELF_ARCH
+#endif
+
 #ifndef ELF_HWCAP
 #define ELF_HWCAP 0
 #endif