build: use allowed over enabled

Meson feature options are typically in a tri-state of enabled, disabled,
or auto.  The enabled and disabled functions on an option (from
`get_option`) no longer return true for auto features.  Instead, the
expectation is to use `allowed()` which is true for both enabled and auto.

Switch all uses of `enabled` to `allowed`.

Change-Id: I37fcb391dcb215a86a60c26f7512f6ccb8312dc4
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/tools/power-utils/meson.build b/tools/power-utils/meson.build
index d9e8a37..e329393 100644
--- a/tools/power-utils/meson.build
+++ b/tools/power-utils/meson.build
@@ -17,6 +17,6 @@
     ]
 )
 
-if get_option('tests').enabled()
+if get_option('tests').allowed()
     subdir('test')
 endif