RDMA/hfi1: Open-code rvt_set_ibdev_name()

RDMA/hfi1: Open-code rvt_set_ibdev_name()

clang warns about a function missing a printf attribute:

include/rdma/rdma_vt.h:457:47: error: diagnostic behavior may be improved by adding the 'format(printf, 2, 3)' attribute to the declaration of 'rvt_set_ibdev_name' [-Werror,-Wmissing-format-attribute]
  447 | static inline void rvt_set_ibdev_name(struct rvt_dev_info *rdi,
      | __attribute__((format(printf, 2, 3)))
  448 |                                       const char *fmt, const char *name,
  449 |                                       const int unit)

The helper was originally added as an abstraction for the hfi1 and
qib drivers needing the same thing, but now qib is gone, and hfi1
is the only remaining user of rdma_vt.

Avoid the warning and allow the compiler to check the format string by
open-coding the helper and directly assigning the device name.

Fixes: 5084c8ff21f2 ("IB/{rdmavt, hfi1, qib}: Self determine driver name")
Link: https://patch.msgid.link/r/20260602140453.3542427-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>