mbuf: remove unneeded atomic generic header include

There is no need for the direct inclusion of the generic/ header [1]
now that we don't use the rte_atomic API anymore.

It was the last case of direct inclusion of the generic/ headers,
so the flag -Wno-unused-function can be dropped.

1: https://git.dpdk.org/dpdk/commit/?id=3eb860b08eb7

Fixes: e41d27a68d ("mbuf: remove atomic reference counters")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

buildtools/chkincs/meson.build

@@ -17,7 +17,6 @@ gen_c_files = generator(gen_c_file_for_header,
 	arguments: ['@INPUT@', '@OUTPUT@'])
 
 cflags = machine_args
-cflags += '-Wno-unused-function' # needed if we include generic headers
 cflags += '-DALLOW_EXPERIMENTAL_API'
 
 sources = files('main.c')

lib/librte_mbuf/rte_mbuf_core.h

@@ -20,7 +20,6 @@
 
 #include <rte_compat.h>
 #include <rte_byteorder.h>
-#include <generic/rte_atomic.h>
 
 #ifdef __cplusplus
 extern "C" {