ASoC: soc-acpi: fix implicit header use of module.h/export.h

This file is implicitly relying on an instance of including
module.h from <linux/acpi.h>.

Ideally, header files under include/linux shouldn't be adding
includes of other headers, in anticipation of their consumers,
but just the headers needed for the header itself to pass
parsing with CPP.

The module.h is particularly bad in this sense, as it itself does
include a whole bunch of other headers, due to the complexity of
module support.

Here, we make the include explicit, in order to allow the future
removal of module.h from linux/acpi.h without causing build breakage.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-acpi.c

@@ -4,6 +4,8 @@
 //
 // Copyright (c) 2013-15, Intel Corporation.
 
+#include <linux/export.h>
+#include <linux/module.h>
 #include <sound/soc-acpi.h>
 
 struct snd_soc_acpi_mach *