selftests/bpf: add architecture-agnostic headers

The BPF selftests fail to build with missing headers
'asm/bitsperlong.h' and 'asm/errno.h'.

These already exist in 'tools/arch/[arch]/include';
add architecture-agnostic header files in 'tools/include/uapi'
to reference them.
Signed-off-by: NSirio Balmelli <sirio@b-ad.ch>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

tools/include/uapi/asm/bitsperlong.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/uapi/asm/bitsperlong.h"
+#elif defined(__aarch64__)
+#include "../../arch/arm64/include/uapi/asm/bitsperlong.h"
+#elif defined(__powerpc__)
+#include "../../arch/powerpc/include/uapi/asm/bitsperlong.h"
+#elif defined(__s390__)
+#include "../../arch/s390/include/uapi/asm/bitsperlong.h"
+#elif defined(__sparc__)
+#include "../../arch/sparc/include/uapi/asm/bitsperlong.h"
+#elif defined(__mips__)
+#include "../../arch/mips/include/uapi/asm/bitsperlong.h"
+#elif defined(__ia64__)
+#include "../../arch/ia64/include/uapi/asm/bitsperlong.h"
+#else
+#include <asm-generic/bitsperlong.h>
+#endif

tools/include/uapi/asm/errno.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#if defined(__i386__) || defined(__x86_64__)
+#include "../../arch/x86/include/uapi/asm/errno.h"
+#elif defined(__powerpc__)
+#include "../../arch/powerpc/include/uapi/asm/errno.h"
+#elif defined(__sparc__)
+#include "../../arch/sparc/include/uapi/asm/errno.h"
+#elif defined(__alpha__)
+#include "../../arch/alpha/include/uapi/asm/errno.h"
+#elif defined(__mips__)
+#include "../../arch/mips/include/uapi/asm/errno.h"
+#elif defined(__ia64__)
+#include "../../arch/ia64/include/uapi/asm/errno.h"
+#elif defined(__xtensa__)
+#include "../../arch/xtensa/include/uapi/asm/errno.h"
+#else
+#include <asm-generic/errno.h>
+#endif