MAINTAINERS: claim maintainership of files with "uniphier" pattern

The pattern "N:    uniphier" can cover
  - drivers/serial/serial_uniphier.c
  - drivers/i2c/i2c-uniphier.c
  - drivers/i2c/i2c-uniphier-f.c
  - arch/arm/dts/uniphier-*

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

MAINTAINERS

@@ -170,7 +170,7 @@ T:	git git://git.denx.de/u-boot-uniphier.git
 F:	arch/arm/cpu/armv7/uniphier/
 F:	arch/arm/include/asm/arch-uniphier/
 F:	configs/ph1_*_defconfig
-F:	drivers/serial/serial_uniphier.c
+N:	uniphier
 
 ARM ZYNQ
 M:	Michal Simek <monstr@monstr.eu>