Revert "perf build: Warn for BPF skeletons if endian mismatches"

This reverts commit 51924ae69e.

We need to better polish building with BPF skels, so revert back to
making it an experimental feature that has to be explicitely enabled
using BUILD_BPF_SKEL=1.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile.config

@@ -663,17 +663,14 @@ ifndef NO_BPF_SKEL
   $(call feature_check,clang-bpf-co-re)
   ifeq ($(feature-clang-bpf-co-re), 0)
     dummy := $(error: ERROR: BPF skeletons unsupported. clang too old/not installed or build with NO_BPF_SKEL=1.)
+  else
+    ifeq ($(filter -DHAVE_LIBBPF_SUPPORT, $(CFLAGS)),)
+      dummy := $(error: ERROR: BPF skeletons unsupported. BPF skeleton support requires libbpf or build with NO_BPF_SKEL=1.)
+    else
+      $(call detected,CONFIG_PERF_BPF_SKEL)
+      CFLAGS += -DHAVE_BPF_SKEL
+    endif
   endif
-  ifeq ($(filter -DHAVE_LIBBPF_SUPPORT, $(CFLAGS)),)
-    dummy := $(error: ERROR: BPF skeletons unsupported. BPF skeleton support requires libbpf or build with NO_BPF_SKEL=1.)
-  endif
-  host_byte_order=$(echo ""|$(HOSTCC) -dM -E -|grep __BYTE_ORDER__)
-  target_byte_order=$(echo ""|$(CC) -dM -E -|grep __BYTE_ORDER__)
-  ifneq ($(host_byte_order), $(target_byte_order))
-    $(warning Possibly mismatched host and target endianness may break BPF skeletons)
-  endif
-  $(call detected,CONFIG_PERF_BPF_SKEL)
-  CFLAGS += -DHAVE_BPF_SKEL
 endif
 
 dwarf-post-unwind := 1