init/version.c: remove #include <generated/utsrelease.h>

Commit 2df8220c ("kbuild: build init/built-in.a just once") moved
the usage of the define UTS_RELEASE to the file version-timestamp.c.

version-timestamp.c in turn is included from version.c but already
includes utsrelease.h itself properly.

The unneeded include of utsrelease.h from version.c can be dropped.

Fixes: 2df8220c ("kbuild: build init/built-in.a just once")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>