policy_unpack_test fails on big endian systems because data byte order
is expected to be little endian but is generated in host byte order.
This results in test failures such as:

 # policy_unpack_test_unpack_array_with_null_name: EXPECTATION FAILED at security/apparmor/policy_unpack_test.c:150
    Expected array_size == (u16)16, but
        array_size == 4096 (0x1000)
        (u16)16 == 16 (0x10)
    # policy_unpack_test_unpack_array_with_null_name: pass:0 fail:1 skip:0 total:1
    not ok 3 policy_unpack_test_unpack_array_with_null_name
    # policy_unpack_test_unpack_array_with_name: EXPECTATION FAILED at security/apparmor/policy_unpack_test.c:164
    Expected array_size == (u16)16, but
        array_size == 4096 (0x1000)
        (u16)16 == 16 (0x10)
    # policy_unpack_test_unpack_array_with_name: pass:0 fail:1 skip:0 total:1

Add the missing endianness conversions when generating test data.

Fixes: 4d944bcd ("apparmor: add AppArmor KUnit tests for policy unpack")
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>