ioping.1: document tera suffixes

Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>

ioping.1

@@ -102,21 +102,24 @@ megabytes
 .TP
 .BR g ,\  gb
 gigabytes
+.TP
+.BR t ,\  tb
+terabytes
 .PP
 For options that expect "number" argument (\fB-p\fR and \fB-c\fR) you
 can optionally specify one of the following suffixes (case-insensitive):
 .TP
-.B da
-deca (tens, 10)
-.TP
 .B k
 kilo (thousands, 1 000)
 .TP
-.B M
+.B m
 mega (millions, 1 000 000)
 .TP
-.B G
+.B g
 giga (billions, 1 000 000 000)
+.TP
+.B t
+tera (trillions, 1 000 000 000 000)
 .SH EXIT STATUS
 Returns \fB0\fR upon success. The following error codes are defined:
 .TP