scsi: message: fusion: Replace deprecated strncpy() with strscpy()

strncpy() is deprecated for use on NUL-terminated destination strings [1]
and as such we should prefer more robust and less ambiguous string
interfaces.

The only caller of mptsas_exp_repmanufacture_info() is
mptsas_probe_one_phy() which can allocate rphy in either
sas_end_device_alloc() or sas_expander_alloc(). Both of which
zero-allocate:

|       rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);

... this is supplied to mptsas_exp_repmanufacture_info() as edev meaning
that no future NUL-padding of edev members is needed.

Considering the above, a suitable replacement is strscpy() [2] due to the
fact that it guarantees NUL-termination on the destination buffer without
unnecessarily NUL-padding.

Also use the more idiomatic strscpy() pattern of (dest, src, sizeof(dest)).

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20231003-strncpy-drivers-message-fusion-mptsas-c-v2-1-5ce07e60bd21@google.com
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>