vsprintf: Update %pGp documentation about that it prints hex value

The commit 23efd080 ("vsprintf: Make %pGp print
the hex value") changed the behavior of %pGp printk format.
Update the documentation accordingly.

Fixes: 23efd080 ("vsprintf: Make %pGp print the hex value")
Reviewed-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/YXlKqCPY9suM4mfT@alley

Documentation/core-api/printk-formats.rst

@@ -580,7 +580,7 @@ Flags bitfields such as page flags, gfp_flags
 
 ::
 
-	%pGp	referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff
+	%pGp	0x17ffffc0002036(referenced|uptodate|lru|active|private|node=0|zone=2|lastcpupid=0x1fffff)
 	%pGg	GFP_USER|GFP_DMA32|GFP_NOWARN
 	%pGv	read|exec|mayread|maywrite|mayexec|denywrite