ACPICA: Headers: Deploy #pragma pack (push) and (pop).

Use push and pop to both guarantee that the correct alignment is used,
and to restore the alignment to whatever it was before the header
was included.

It is reported that the #pragma pack(push/pop) directives are not supported
by the specific GCCs, but this patch still doesn't affect kernel build
as there are already #pragma pack([1]) directives used in the old ACPICA
headers, which means there shouldn't be GCCs that are currently used to
compile the ACPI kernels do not support #pragma pack() directives.

References: https://bugs.acpica.org/show_bug.cgi?id=1058
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpica/acresrc.h

@@ -48,6 +48,8 @@
 
 #include "amlresrc.h"
 
+#pragma pack(push)		/* Set default struct packing */
+
 /*
  * If possible, pack the following structures to byte alignment, since we
  * don't care about performance for debug output. Two cases where we cannot
@@ -378,4 +380,6 @@ extern struct acpi_rsdump_info acpi_rs_dump_uart_serial_bus[];
 extern struct acpi_rsdump_info acpi_rs_dump_general_flags[];
 #endif
 
+#pragma pack(pop)		/* Restore original struct packing */
+
 #endif				/* __ACRESRC_H__ */