Revert "PPC: Fail configure when libfdt is not available"

This reverts commit f90a9d02.
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

configure

@@ -3454,16 +3454,7 @@ case "$target_arch2" in
       fi
     fi
 esac
-if test "$fdt" != "yes" && test "$target_arch2" = "ppc" -o \
-        "$target_arch2" = "ppc64" -o "$target_arch2" = "ppcemb"; then
-  echo
-  echo "Error: libfdt missing"
-  echo "The PowerPC target requires libfdt to work properly."
-  echo "Please make sure to have it and its development packages installed."
-  echo
-  exit 1
-fi
-if test "$target_arch2" = "ppc64"; then
+if test "$target_arch2" = "ppc64" -a "$fdt" = "yes"; then
   echo "CONFIG_PSERIES=y" >> $config_target_mak
 fi
 if test "$target_bigendian" = "yes" ; then