systemd: Drop 0016-Hide-__start_BUS_ERROR_MAP-and-__stop_BUS_ERROR_MAP.patch

systemd: Drop 0016-Hide-__start_BUS_ERROR_MAP-and-__stop_BUS_ERROR_MAP.patch

This patch was effectively needed when usng gold linker but it has been
fixed in binutils [1], it was seen in systemd as well [2]

This however, should not happen with latest binutils and systemd has
already reverted the fix since it was a tool error

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=18548
[2] https://github.com/systemd/systemd/issues/234

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>