Fix mcu option

If the mcu temp sensor is not included in a build, it isn't showing up.
This is due to meson_options.txt having 2 different names for mcu;  mcu,
and mcu-temp.  The upstream recipe uses mcu to key, so lets just do
that.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ib84c96b97c534c81e9e4e83c838dffe4e26b6957
diff --git a/src/meson.build b/src/meson.build
index ad53332..dc11177 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -134,7 +134,7 @@
     )
 endif
 
-if get_option('mcu-temp').enabled()
+if get_option('mcu').enabled()
     executable(
         'mcutempsensor',
         'MCUTempSensor.cpp',