squashfs: only remove /boot from squashfs image

target/share/squashfs/build.sh

@@ -29,10 +29,7 @@ SQUASHFS_POSTOVERLAY_HOOK=
 # Lists
 #
 SQUASHFS_INSTALL_PACKAGES=
-SQUASHFS_INSTALL_PATTERN="-e '/ boot/d;' \
-	-e '/ var\/adm/ d;' \
-	-e '/\.\(h\|o\|a\|a\..*\|la\|pc\)$/d;' -e '/\/aclocal\//d;' \
-	-e '/ usr\/share\/\(doc\|info\|man\)\//d;' -e'/ opt\/[^\/]*\/\(doc\|info\|man\)\//d;' -e '/\/gtk-doc\//d;'"
+SQUASHFS_INSTALL_PATTERN="-e '/ boot/d;'"
 
 SQUASHFS_EMPTY_PATTERN="-e '/\.\/lib\/udev\/devices\//d;'"