perf cap: Add __NR_capget to arch/x86 unistd

As there are duplicated kernel headers in tools/include libc can pick
up the wrong definitions. This was causing the wrong system call for
capget in perf.

Reported-by: Adrian Hunter <[e-mail]>
Fixes: e25ebda78e230283 ("perf cap: Tidy up and improve capability testing")
Closes: https://lore.kernel.org/lkml/[e-mail]/
Signed-off-by: Ian Rogers <[e-mail]>
Tested-by: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/arch/x86/include/uapi/asm/unistd_32.h

···
 #ifndef __NR_getpgid
 #define __NR_getpgid 132
 #endif
+#ifndef __NR_capget
+#define __NR_capget 184
+#endif
 #ifndef __NR_gettid
 #define __NR_gettid 224
 #endif

tools/arch/x86/include/uapi/asm/unistd_64.h

···
 #ifndef __NR_getpgid
 #define __NR_getpgid 121
 #endif
+#ifndef __NR_capget
+#define __NR_capget 125
+#endif
 #ifndef __NR_gettid
 #define __NR_gettid 186
 #endif

tools/perf/util/cap.c

···
 #include "debug.h"
 #include <errno.h>
 #include <string.h>
-#include <unistd.h>
 #include <linux/capability.h>
 #include <sys/syscall.h>
-
-#ifndef SYS_capget
-#define SYS_capget 90
-#endif
+#include <unistd.h>
 
 #define MAX_LINUX_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
 
···
 {
 	struct __user_cap_header_struct header = {
 		.version = _LINUX_CAPABILITY_VERSION_3,
-		.pid = getpid(),
+		.pid = 0,
 	};
-	struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S];
+	struct __user_cap_data_struct data[MAX_LINUX_CAPABILITY_U32S] = {};
 	__u32 cap_val;
 
 	*used_root = false;