Staging: delete spectra driver

To quote Alan:
	Moorestown/Oaktrail has appeared only in the PC like form so the
	following bits of staging can be binned:

	drivers/staging/spectra

so let's delete it.

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>