kconfig: source autogenerated Kconfig.dts earlier than defconfigs

In addition to the DT_HAS_<compat>_ENABLED options, the autogenerated
Kconfig.dts file also provides the DT_COMPAT_<compat> *macros* which avoid
manually declaring them when working around the no comma limitation. Unlike
options which can be referenced before their declaration, macros MUST
be defined before their usage (otherwise, they expand to nothing ("")).

Because the defconfig files were sourced before "dts/Kconfig", it was not
possible to use the DT_COMPAT macros from shields/boards/SoC defconfig;
this is not only confusing but also suboptimal because the macros must be
defined manually.

Include "dts/Kconfig" earlier to allow usage of the DT_COMPAT macros from
shields, boards and SoC defconfig. This should have no adverse effect
since there is no reason to override the options provided by the
autogenerated Kconfig.dts anyways.

Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>

Kconfig.zephyr

@@ -9,6 +9,10 @@ source "Kconfig.constants"
 
 osource "$(APPLICATION_SOURCE_DIR)/VERSION"
 
+# This should be sourced early since the autogen Kconfig.dts options
+# and macros may get used by shields/boards/SoC defconfig or modules.
+source "dts/Kconfig"
+
 # Include Kconfig.defconfig files first so that they can override defaults and
 # other symbol/choice properties by adding extra symbol/choice definitions.
 # After merging all definitions for a symbol/choice, Kconfig picks the first
@@ -33,10 +37,6 @@ osource "$(TOOLCHAIN_KCONFIG_DIR)/Kconfig.defconfig"
 # This loads the testsuite defconfig
 source "subsys/testsuite/Kconfig.defconfig"
 
-# This should be early since the autogen Kconfig.dts symbols may get
-# used by modules
-source "dts/Kconfig"
-
 menu "Modules"
 
 source "modules/Kconfig"