io_uring/cmd: axe duplicate io_uring_cmd_import_fixed_vec() declaration

io_uring/cmd: axe duplicate io_uring_cmd_import_fixed_vec() declaration

io_uring_cmd_import_fixed_vec() is declared in both
include/linux/io_uring/cmd.h and io_uring/uring_cmd.h. The declarations
are identical (if redundant) for CONFIG_IO_URING=y. But if
CONFIG_IO_URING=N, include/linux/io_uring/cmd.h declares the function as
static inline while io_uring/uring_cmd.h declares it as extern. This
causes linker errors if the declaration in io_uring/uring_cmd.h is used.

Remove the declaration in io_uring/uring_cmd.h to avoid linker errors
and prevent the declarations getting out of sync.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Fixes: ef4902752972 ("io_uring/cmd: introduce io_uring_cmd_import_fixed_vec")
Link: https://lore.kernel.org/r/20250520193337.1374509-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>