accel/tcg/plugin: Remove CONFIG_SOFTMMU_GATE definition

The CONFIG_SOFTMMU_GATE definition was never used, remove it.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240313213339.82071-2-philmd@linaro.org>

accel/tcg/plugin-gen.c

@@ -57,12 +57,6 @@
 #include "exec/helper-info.c.inc"
 #undef  HELPER_H
 
-#ifdef CONFIG_SOFTMMU
-# define CONFIG_SOFTMMU_GATE 1
-#else
-# define CONFIG_SOFTMMU_GATE 0
-#endif
-
 /*
  * plugin_cb_start TCG op args[]:
  * 0: enum plugin_gen_from