Staging: spectra: depend on X86_MRST

lld_nand fails to build on arches without virt_to_bus. Since this driver
is specifically for hardware enablment on Moorestown, this patch adds
Moorestown MID support as a dependency.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>