netfilter: ebtables: use __u8 instead of uint8_t in uapi header

When CONFIG_UAPI_HEADER_TEST=y, exported headers are compile-tested to
make sure they can be included from user-space.

Currently, linux/netfilter_bridge/ebtables.h is excluded from the test
coverage. To make it join the compile-test, we need to fix the build
errors attached below.

For a case like this, we decided to use __u{8,16,32,64} variable types
in this discussion:

  https://lkml.org/lkml/2019/6/5/18

Build log:

  CC      usr/include/linux/netfilter_bridge/ebtables.h.s
In file included from <command-line>:32:0:
./usr/include/linux/netfilter_bridge/ebtables.h:126:4: error: unknown type name ‘uint8_t’
    uint8_t revision;
    ^~~~~~~
./usr/include/linux/netfilter_bridge/ebtables.h:139:4: error: unknown type name ‘uint8_t’
    uint8_t revision;
    ^~~~~~~
./usr/include/linux/netfilter_bridge/ebtables.h:152:4: error: unknown type name ‘uint8_t’
    uint8_t revision;
    ^~~~~~~
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/uapi/linux/netfilter_bridge/ebtables.h

@@ -123,7 +123,7 @@ struct ebt_entry_match {
 	union {
 		struct {
 			char name[EBT_EXTENSION_MAXNAMELEN];
-			uint8_t revision;
+			__u8 revision;
 		};
 		struct xt_match *match;
 	} u;
@@ -136,7 +136,7 @@ struct ebt_entry_watcher {
 	union {
 		struct {
 			char name[EBT_EXTENSION_MAXNAMELEN];
-			uint8_t revision;
+			__u8 revision;
 		};
 		struct xt_target *watcher;
 	} u;
@@ -149,7 +149,7 @@ struct ebt_entry_target {
 	union {
 		struct {
 			char name[EBT_EXTENSION_MAXNAMELEN];
-			uint8_t revision;
+			__u8 revision;
 		};
 		struct xt_target *target;
 	} u;

usr/include/Makefile

@@ -38,7 +38,6 @@ header-test- += linux/ivtv.h
 header-test- += linux/jffs2.h
 header-test- += linux/kexec.h
 header-test- += linux/matroxfb.h
-header-test- += linux/netfilter_bridge/ebtables.h
 header-test- += linux/netfilter_ipv4/ipt_LOG.h
 header-test- += linux/netfilter_ipv6/ip6t_LOG.h
 header-test- += linux/nfc.h