gcc-plugins: Fix definition of DISABLE_LATENT_ENTROPY_PLUGIN

The variable DISABLE_LATENT_ENTROPY_PLUGIN is defined when
CONFIG_PAX_LATENT_ENTROPY is set. This is leftover from the original PaX
version of the plugin code and doesn't actually exist. Change the condition
to depend on CONFIG_GCC_PLUGIN_LATENT_ENTROPY instead.

Fixes: 38addce8b600 ("gcc-plugins: Add latent_entropy plugin")
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

scripts/Makefile.gcc-plugins

@@ -8,7 +8,7 @@ ifdef CONFIG_GCC_PLUGINS
 
   gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)	+= latent_entropy_plugin.so
   gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY)	+= -DLATENT_ENTROPY_PLUGIN
-  ifdef CONFIG_PAX_LATENT_ENTROPY
+  ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
     DISABLE_LATENT_ENTROPY_PLUGIN			+= -fplugin-arg-latent_entropy_plugin-disable
   endif