weston: Restore partial clients for i.MX 6 and 7
The clients configuration for fbdev was recently removed from
meta-freescale [1] because of the following error:
```
| Run-time dependency gbm found: NO (tried pkgconfig and cmake)
|
| clients/meson.build:134:4: ERROR: Problem encountered: weston-simple-dmabuf-egl requires gbm which was not found. If you rather not build this, drop "dmabuf-egl" from simple-clients option.
```
[1]
eda44e49618610c13ebe4c026cd4981b404a1543
It was also removed for non-Wayland from OE-core [2] because of the
following error in the same client dmabuf-egl:
```
clients/meson.build:141:4: ERROR: Problem encountered: weston-simple-dmabuf-egl
requires option renderer-gl which is not enabled. If you rather not build this,
drop "dmabuf-egl" from simple-clients option.
```
[2]
9b1d30810eeecb46b977c8eed68be69aef891312
Restore the working subset of clients.
Signed-off-by: Tom Hochstein <tom.hochstein@nxp.com>
