perf docs: Refine the description for the buffer size

Current description for the AUX trace buffer size is misleading. When a
user specifies the option '-m,512M', it represents a size value in bytes
(512MiB) but not 512M pages (512M x 4KiB regard to a page of 4KiB).

Make the document clear that the normal buffer and the AUX tracing
buffer share the same semantics. Syncs the documents for consistent
text.

Reviewed-by: James Clark <[e-mail]>
Signed-off-by: Leo Yan <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kan Liang <[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/perf/Documentation/perf-kvm.txt

···
 
 -m::
 --mmap-pages=::
-    Number of mmap data pages (must be a power of two) or size
-    specification with appended unit character - B/K/M/G. The
-    size is rounded up to have nearest pages power of two value.
+        Number of mmap data pages (must be a power of two) or size
+        specification in bytes with appended unit character - B/K/M/G.
+        The size is rounded up to the nearest power-of-two page value.
 
 -a::
 --all-cpus::

tools/perf/Documentation/perf-record.txt

···
 -m::
 --mmap-pages=::
 	Number of mmap data pages (must be a power of two) or size
-	specification with appended unit character - B/K/M/G. The
-	size is rounded up to have nearest pages power of two value.
-	Also, by adding a comma, the number of mmap pages for AUX
-	area tracing can be specified.
+	specification in bytes with appended unit character - B/K/M/G.
+	The size is rounded up to the nearest power-of-two page value.
+	By adding a comma, an additional parameter with the same
+	semantics used for the normal mmap areas can be specified for
+	AUX tracing area.
 
 -g::
 	Enables call-graph (stack chain/backtrace) recording for both

tools/perf/Documentation/perf-top.txt

···
 -m <pages>::
 --mmap-pages=<pages>::
 	Number of mmap data pages (must be a power of two) or size
-	specification with appended unit character - B/K/M/G. The
-	size is rounded up to have nearest pages power of two value.
+	specification in bytes with appended unit character - B/K/M/G.
+	The size is rounded up to the nearest power-of-two page value.
 
 -p <pid>::
 --pid=<pid>::

tools/perf/Documentation/perf-trace.txt

···
 -m::
 --mmap-pages=::
 	Number of mmap data pages (must be a power of two) or size
-	specification with appended unit character - B/K/M/G. The
-	size is rounded up to have nearest pages power of two value.
+	specification in bytes with appended unit character - B/K/M/G.
+	The size is rounded up to the nearest power-of-two page value.
 
 -C::
 --cpu::