tracing: Fix kconfig warning due to a typo

Commit f3f096cfe ("tracing: Provide trace events interface for
uprobes") throws a warning about unmet dependencies.

The exact warning message is:
warning: (UPROBE_EVENT) selects UPROBES which has unmet direct dependencies (UPROBE_EVENTS && PERF_EVENTS)

This is due to a typo in arch/Kconfig file. Fix similar typos in
the uprobetracer documentation.

Also add sample format of a uprobe event in the uprobetracer
documentation as suggested by Masami Hiramatsu.

Reported-by: Stephen Boyd <[e-mail]>
Reported-by: Ingo Molnar <[e-mail]>
Signed-off-by: Srikar Dronamraju <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Ananth N Mavinakayanahalli <[e-mail]>
Cc: Oleg Nesterov <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Anton Arapov <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

Documentation/trace/uprobetracer.txt

···
 Overview
 --------
 Uprobe based trace events are similar to kprobe based trace events.
-To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
+To enable this feature, build your kernel with CONFIG_UPROBE_EVENT=y.
 
 Similar to the kprobe-event tracer, this doesn't need to be activated via
 current_tracer. Instead of that, add probe points via
···
 uprobe_events file.
 
     # cat uprobe_events
-    p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420
+    p:uprobes/p_zsh_0x46420 /bin/zsh:0x00046420 arg1=%ip arg2=%ax
+
+The format of events can be seen by viewing the file events/uprobes/p_zsh_0x46420/format
+
+    # cat events/uprobes/p_zsh_0x46420/format
+    name: p_zsh_0x46420
+    ID: 922
+    format:
+	field:unsigned short common_type;	offset:0;	size:2;	signed:0;
+	field:unsigned char common_flags;	offset:2;	size:1;	signed:0;
+	field:unsigned char common_preempt_count;	offset:3;	size:1;	signed:0;
+	field:int common_pid;	offset:4;	size:4;	signed:1;
+	field:int common_padding;	offset:8;	size:4;	signed:1;
+
+	field:unsigned long __probe_ip;	offset:12;	size:4;	signed:0;
+	field:u32 arg1;	offset:16;	size:4;	signed:0;
+	field:u32 arg2;	offset:20;	size:4;	signed:0;
+
+    print fmt: "(%lx) arg1=%lx arg2=%lx", REC->__probe_ip, REC->arg1, REC->arg2
 
 Right after definition, each event is disabled by default. For tracing these
 events, you need to enable it by:

arch/Kconfig

···
 
 config UPROBES
 	bool "Transparent user-space probes (EXPERIMENTAL)"
-	depends on UPROBE_EVENTS && PERF_EVENTS
+	depends on UPROBE_EVENT && PERF_EVENTS
 	default n
 	help
 	  Uprobes is the user-space counterpart to kprobes: they