local.conf.sample.extended: remove redundant RUNTIMETARGET assignment

This has been fixed in the GCC recipe, so remove from
local.conf.sample.extended.

(From meta-yocto rev: f19f3a7a5286cabf42a0f6d0ea8f7841dc043324)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-poky/conf/local.conf.sample.extended

@@ -321,7 +321,6 @@ DISTRO_FEATURES_remove = "x11"
 # show an example of how it can be done
 # You'll also need your fortran recipe to depend on libgfortran
 #FORTRAN_forcevariable = ",fortran"
-#RUNTIMETARGET_append_pn-gcc-runtime = " libquadmath"
 
 #
 # Kernel image features