dtc: Update requirement to v1.4.2

In order to obtain fdt_first_subnode & fdt_next_subnode symbols from
libfdt for use by a later patch, bump the requirement for dtc to v1.4.2
& the submodule to that same version.

Signed-off-by: Paul Burton <[email protected]>
Reviewed-by: Yongbok Kim <[email protected]>
Signed-off-by: Yongbok Kim <[email protected]>

configure

@@ -3396,11 +3396,11 @@ fi
 if test "$fdt" != "no" ; then
   fdt_libs="-lfdt"
   # explicitly check for libfdt_env.h as it is missing in some stable installs
-  # and test for required functions to make sure we are on a version >= 1.4.0
+  # and test for required functions to make sure we are on a version >= 1.4.2
   cat > $TMPC << EOF
 #include <libfdt.h>
 #include <libfdt_env.h>
-int main(void) { fdt_get_property_by_offset(0, 0, 0); return 0; }
+int main(void) { fdt_first_subnode(0, 0); return 0; }
 EOF
   if compile_prog "" "$fdt_libs" ; then
     # system DTC is good - use it
@@ -3418,7 +3418,7 @@ EOF
     fdt_libs="-L\$(BUILD_DIR)/dtc/libfdt $fdt_libs"
   elif test "$fdt" = "yes" ; then
     # have neither and want - prompt for system/submodule install
-    error_exit "DTC (libfdt) version >= 1.4.0 not present. Your options:" \
+    error_exit "DTC (libfdt) version >= 1.4.2 not present. Your options:" \
         "  (1) Preferred: Install the DTC (libfdt) devel package" \
         "  (2) Fetch the DTC submodule, using:" \
         "      git submodule update --init dtc"