ACPI: proc: Remove unused header

With `make W=1` build we get a warning:

drivers/acpi/proc.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present

Fix it by removing unused inclusion.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://patch.msgid.link/20250612201321.3536493-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: andy-shev

drivers/acpi/proc.c

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
-#include <linux/export.h>
 #include <linux/suspend.h>
 #include <linux/bcd.h>
 #include <linux/acpi.h>