ARM: gemini: fix compiler warning due wrong data type

This patch fixes a compiler warning in gemini_restart()
issued by commit 7b6d864b ("reboot:arm: reboot_mode
changes from char to enum reboot_mode").

arch/arm/mach-gemini/board-rut1xx.c:93:2: warning: initialization from incompatible pointer type

The warning is harmless, and the patch does not need to
be backported to stable kernels.

Fixes: 7b6d864b

 ("reboot:arm: reboot_mode changes from char to enum reboot_mode.")
Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>