git-mailrc: add me as a maintainer of UniPhier platform

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

doc/git-mailrc

@@ -63,6 +63,7 @@ alias sunxi          uboot, ijc, jwrdegoede
 alias tegra          uboot, sjg, Tom Warren <twarren@nvidia.com>, Stephen Warren <swarren@nvidia.com>
 alias tegra2         tegra
 alias ti             uboot, trini
+alias uniphier       uboot, masahiro
 alias zynq           uboot, monstr
 
 alias avr32          uboot, abiessmann