usr/gen_init_cpio.c: remove unnecessary -1 values from int file

The file variable is assigned first, it does not need to be initialized.

Link: https://lkml.kernel.org/r/20220919014406.3242-1-zeming@nfschina.com
Signed-off-by: Li zeming <zeming@nfschina.com>
Cc: Li zeming <zeming@nfschina.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>