linux-imx

sh: remove unused rtc_sh_get/set_time infrastructure

All platforms are now converted to RTC drivers, so this has become
obsolete. The board_time_init() callback still has one caller, but
could otherwise also get killed.

This removes one more usage of the deprecated timespec structure,
which overflows in y2038.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>