local.conf.sample.extended: fix double 'of' typo

Remove the redundant 'of' word in the INITRAMFS_IMAGE comment.

(From meta-yocto rev: 200b05182c74f3f4f778907d5ee92831adb3d77e)

Signed-off-by: Vivien Didelot <vdidelot@pbsc.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

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

@@ -325,7 +325,7 @@ DISTRO_FEATURES_remove = "x11"
 # The INITRAMFS_IMAGE image variable will cause an additional recipe to
 # be built as a dependency to the what ever rootfs recipe you might be
 # using such as core-image-sato.  The initramfs might be needed for
-# the initial boot of of the target system such as to load kernel
+# the initial boot of the target system such as to load kernel
 # modules prior to mounting the root file system.
 #
 # INITRAMFS_IMAGE_BUNDLE variable controls if the image recipe