acpi: Remove header dependency

In order to avoid future header hell, remove the inclusion of
proc_fs.h from acpi_bus.h. All it needs is a forward declaration of a
struct.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lkml.kernel.org/r/20200321113241.246190285@linutronix.de

drivers/platform/x86/wmi.c

@@ -29,6 +29,7 @@
 #include <linux/uaccess.h>
 #include <linux/uuid.h>
 #include <linux/wmi.h>
+#include <linux/fs.h>
 #include <uapi/linux/wmi.h>
 
 ACPI_MODULE_NAME("wmi");