mailmap: Fix broken email from fit_image.c

The patch
"tools/mkimage: Fix DTC run command to handle file names with space"
(sha1: a6e9810495bc929b6beafb88f557cdaadf87fc83) contains comma in name
which is confusing patman. Fix it by defining Mirza's email in mailmap.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

.mailmap

@@ -34,3 +34,4 @@ Wolfgang Denk <wdenk>
 York Sun <yorksun@freescale.com>
 York Sun <york.sun@nxp.com>
 Łukasz Majewski <l.majewski@samsung.com>
+Mirza <Taimoor_Mirza@mentor.com>