eal: deprecate old cpu features check function

It's likely that this function isn't used anywhere, but since it was part
of the public API, mark the function for deprecation for at least one
release.

Signed-off-by: Aaron Conole <aconole@redhat.com>

lib/librte_eal/common/include/generic/rte_cpuflags.h

@@ -39,6 +39,7 @@
  * Architecture specific API to determine available CPU features at runtime.
  */
 
+#include "rte_common.h"
 #include <errno.h>
 
 /**
@@ -79,6 +80,7 @@ rte_cpu_get_flag_enabled(enum rte_cpu_flag_t feature);
  * that were specified at compile time. It is called automatically within the
  * EAL, so does not need to be used by applications.
  */
+__rte_deprecated
 void
 rte_cpu_check_supported(void);