apparmor: use get_unaligned() only for multi-byte words

Using get_unaligned() on a u8 pointer is pointless, and will
result in a compiler warning after a planned cleanup:

In file included from arch/x86/include/generated/asm/unaligned.h:1,
                 from security/apparmor/policy_unpack.c:16:
security/apparmor/policy_unpack.c: In function 'unpack_u8':
include/asm-generic/unaligned.h:13:15: error: 'packed' attribute ignored for field of type 'u8' {aka 'unsigned char'} [-Werror=attributes]
   13 |  const struct { type x __packed; } *__pptr = (typeof(__pptr))(ptr); \
      |               ^

Simply dereference this pointer directly.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: John Johansen <john.johansen@canonical.com>

security/apparmor/policy_unpack.c

@@ -304,7 +304,7 @@ static bool unpack_u8(struct aa_ext *e, u8 *data, const char *name)
 		if (!inbounds(e, sizeof(u8)))
 			goto fail;
 		if (data)
-			*data = get_unaligned((u8 *)e->pos);
+			*data = *((u8 *)e->pos);
 		e->pos += sizeof(u8);
 		return true;
 	}