mfd: db8500-prcmu: 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.

We expect project_name to be NUL-terminated based on its use with
pr_info:
| 	pr_info("PRCMU firmware: %s(%d), version %d.%d.%d\n",
| 		fw_info.version.project_name,
| 		fw_info.version.project,
| 		fw_info.version.api_version,
| 		fw_info.version.func_version,
| 		fw_info.version.errata);

Moreover, NUL-padding does not seem to be 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.

Let's also change `PRCMU_FW_PROJECT_NAME_LEN` to just
sizeof(fw_info.version.project_name) as this is more idiomatic strscpy
usage.

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
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230927-strncpy-drivers-mfd-db8500-prcmu-c-v1-1-db9693f92a68@google.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/mfd/db8500-prcmu.c

@@ -2639,9 +2639,9 @@ static void dbx500_fw_version_init(struct device_node *np)
 	fw_info.version.api_version = (version >> 8) & 0xFF;
 	fw_info.version.func_version = (version >> 16) & 0xFF;
 	fw_info.version.errata = (version >> 24) & 0xFF;
-	strncpy(fw_info.version.project_name,
+	strscpy(fw_info.version.project_name,
 		fw_project_name(fw_info.version.project),
-		PRCMU_FW_PROJECT_NAME_LEN);
+		sizeof(fw_info.version.project_name));
 	fw_info.valid = true;
 	pr_info("PRCMU firmware: %s(%d), version %d.%d.%d\n",
 		fw_info.version.project_name,