mkfontscale: upgrade 1.2.1 -> 1.2.2

temporarily override SRC_URI which is hard-coded in xorg-app-common.inc
since new versions of packages use a new compression format - .tar.xz

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>