exec: do not define use_icount for user-mode emulation

use_icount is also defined by stubs/cpu-get-icount.c, we do not need
to have a useless definition in exec.c.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <20200204161036.20889-1-pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

exec.c

@@ -98,15 +98,15 @@ CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus);
 /* current CPU in the current thread. It is only valid inside
    cpu_exec() */
 __thread CPUState *current_cpu;
-/* 0 = Do not count executed instructions.
-   1 = Precise instruction counting.
-   2 = Adaptive rate instruction counting.  */
-int use_icount;
 
 uintptr_t qemu_host_page_size;
 intptr_t qemu_host_page_mask;
 
 #if !defined(CONFIG_USER_ONLY)
+/* 0 = Do not count executed instructions.
+   1 = Precise instruction counting.
+   2 = Adaptive rate instruction counting.  */
+int use_icount;
 
 typedef struct PhysPageEntry PhysPageEntry;