package/wpebackend-fdo: bump to version 1.2.1

Update the package to version 1.2.1, which includes build fixes.
Patch "0001-Improve-how-CMake-looks-for-wayland-scanner.patch" is
now included and therefore can be removed from Buildroot.

Signed-off-by: Adrian Perez de Castro <aperez@igalia.com>
Acked-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>