tracing: Modify print_fields() for fields output order

Now the print_fields() print trace event fields in reverse order. Modify
it to the positive sequence.

Example outputs for a user event:
	test0 u32 count1; u32 count2

Output before:
	example-2547    [000] .....   325.666387: test0: count2=0x2 (2) count1=0x1 (1)

Output after:
	example-2742    [002] .....   429.769370: test0: count1=0x1 (1) count2=0x2 (2)

Link: https://lore.kernel.org/linux-trace-kernel/20230525085232.5096-1-sunliming@kylinos.cn



Fixes: 80a76994 ("tracing: Add "fields" option to show raw trace event fields")
Signed-off-by: sunliming <sunliming@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>