MAINTAINERS: Fix the classification of bios-tables-test-allowed-diff.h

The file tests/qtest/bios-tables-test-allowed-diff.h is currently only
assigned to the qtest section according MAINTAINERS. However, this file
normally only gets updated when the ACPI tables changed - something the
qtest maintainers don't have much clue of. Thus this file should rather
be assigned to the ACPI maintainers instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20200607052022.12222-1-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

MAINTAINERS

@@ -1531,7 +1531,7 @@ F: hw/acpi/*
 F: hw/smbios/*
 F: hw/i386/acpi-build.[hc]
 F: hw/arm/virt-acpi-build.c
-F: tests/qtest/bios-tables-test.c
+F: tests/qtest/bios-tables-test*
 F: tests/qtest/acpi-utils.[hc]
 F: tests/data/acpi/
 
@@ -2321,6 +2321,7 @@ S: Maintained
 F: qtest.c
 F: accel/qtest.c
 F: tests/qtest/
+X: tests/qtest/bios-tables-test-allowed-diff.h
 
 Device Fuzzing
 M: Alexander Bulekov <alxndr@bu.edu>