perf hashmap: Tidy hashmap dependency

When libbpf is present the build uses definitions in libbpf hashmap.c,
however, libbpf's hashmap.h wasn't being used. Switch to using the
correct hashmap.h dependent on the define HAVE_LIBBPF_SUPPORT. This was
the original intent in:

  https://lore.kernel.org/lkml/20200515221732.44078-8-irogers@google.com/Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20220824050604.352156-1-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/bpf-loader.c

@@ -27,7 +27,11 @@
 #include "util.h"
 #include "llvm-utils.h"
 #include "c++/clang-c.h"
-#include "hashmap.h"
+#ifdef HAVE_LIBBPF_SUPPORT
+#include <bpf/hashmap.h>
+#else
+#include "util/hashmap.h"
+#endif
 #include "asm/bug.h"
 
 #include <internal/xyarray.h>

tools/perf/util/evsel.c

@@ -46,7 +46,11 @@
 #include "string2.h"
 #include "memswap.h"
 #include "util.h"
-#include "hashmap.h"
+#ifdef HAVE_LIBBPF_SUPPORT
+#include <bpf/hashmap.h>
+#else
+#include "util/hashmap.h"
+#endif
 #include "pmu-hybrid.h"
 #include "off_cpu.h"
 #include "../perf-sys.h"

tools/perf/util/expr.h

@@ -2,14 +2,11 @@
 #ifndef PARSE_CTX_H
 #define PARSE_CTX_H 1
 
-// There are fixes that need to land upstream before we can use libbpf's headers,
-// for now use our copy unconditionally, since the data structures at this point
-// are exactly the same, no problem.
-//#ifdef HAVE_LIBBPF_SUPPORT
-//#include <bpf/hashmap.h>
-//#else
+#ifdef HAVE_LIBBPF_SUPPORT
+#include <bpf/hashmap.h>
+#else
 #include "util/hashmap.h"
-//#endif
+#endif
 
 struct metric_ref;
 

tools/perf/util/stat.c

@@ -14,7 +14,11 @@
 #include "evlist.h"
 #include "evsel.h"
 #include "thread_map.h"
-#include "hashmap.h"
+#ifdef HAVE_LIBBPF_SUPPORT
+#include <bpf/hashmap.h>
+#else
+#include "util/hashmap.h"
+#endif
 #include <linux/zalloc.h>
 
 void update_stats(struct stats *stats, u64 val)