ASoC: intel: include linux/module.h as needed

The MODULE_DESCRIPTION() macro is only available when including
the linux/module.h header. Apparently this is included indirectly
from sst-firmware.c in some configurations, but not in others:

sound/soc/intel/common/sst-firmware.c:1278:20: error: expected declaration specifiers or '...' before string constant
 MODULE_DESCRIPTION("Intel SST Firmware Loader");
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
sound/soc/intel/common/sst-firmware.c:1279:16: error: expected declaration specifiers or '...' before string constant

This adds the missing include line.

Fixes: a395bdd6

 ("ASoC: intel: Fix sst-dsp dependency on dw stuff")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@kernel.org>