meson: make wrapper options sub-command specific

The meson-wrapper adds setup options to facilitate cross-compilation.
The current options are exclusive to the setup sub-command and might
cause issues with other sub-commands.

Update the wrapper to make options sub-command specific.

Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>