Revert "selftests: vDSO: parse_vdso: Use UAPI headers instead of libc headers"

This reverts commit c9fbaa8795 ("selftests: vDSO: parse_vdso: Use UAPI
headers instead of libc headers")

The kernel headers were used to make parse_vdso.c compatible with
nolibc.  Unfortunately linux/elf.h is incompatible with glibc's
sys/auxv.h. When using glibc it is therefore not possible build
parse_vdso.c as part of the same compilation unit as its caller
as sys/auxv.h is needed for getauxval().

In the meantime nolibc gained its own elf.h, providing compatibility
with the documented libc interfaces.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260227-vdso-selftest-cleanups-v2-1-d84830fa8beb@linutronix.de

tools/testing/selftests/vDSO/Makefile

@@ -19,8 +19,6 @@ endif
 
 include ../lib.mk
 
-CFLAGS += $(TOOLS_INCLUDES)
-
 CFLAGS_NOLIBC := -nostdlib -nostdinc -ffreestanding -fno-asynchronous-unwind-tables \
 		 -fno-stack-protector -include $(top_srcdir)/tools/include/nolibc/nolibc.h \
 		 -I$(top_srcdir)/tools/include/nolibc/ $(KHDR_INCLUDES)

tools/testing/selftests/vDSO/parse_vdso.c

@@ -19,8 +19,7 @@
 #include <stdint.h>
 #include <string.h>
 #include <limits.h>
-#include <linux/auxvec.h>
-#include <linux/elf.h>
+#include <elf.h>
 
 #include "parse_vdso.h"