stubs: Remove unused arch_type.c stub

We added a stub for the arch_type global in commit 5964ed56 so
that we could compile blockdev.c into the tools.  However, in commit
9db1d3a2 we removed the only use of arch_type from blockdev.c.
The stub is therefore no longer needed, and we can delete it again,
together with the QEMU_ARCH_NONE value that only the stub was using.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210730105947.28215-9-peter.maydell@linaro.org

include/sysemu/arch_init.h

@@ -24,8 +24,6 @@ enum {
     QEMU_ARCH_RX = (1 << 20),
     QEMU_ARCH_AVR = (1 << 21),
     QEMU_ARCH_HEXAGON = (1 << 22),
-
-    QEMU_ARCH_NONE = (1 << 31),
 };
 
 extern const uint32_t arch_type;

stubs/arch_type.c

-#include "qemu/osdep.h"
-#include "sysemu/arch_init.h"
-
-const uint32_t arch_type = QEMU_ARCH_NONE;

stubs/meson.build

-stub_ss.add(files('arch_type.c'))
 stub_ss.add(files('bdrv-next-monitor-owned.c'))
 stub_ss.add(files('blk-commit-all.c'))
 stub_ss.add(files('blk-exp-close-all.c'))