soc: loongson: loongson2_guts: Add check for devm_kstrdup()

Add check for the return value of devm_kstrdup() in
loongson2_guts_probe() to catch potential exception.

Fixes: b82621ac ("soc: loongson: add GUTS driver for loongson-2 platforms")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
Link: https://lore.kernel.org/r/20250220081714.2676828-1-haoxiang_li2024@163.com


Signed-off-by: Arnd Bergmann <arnd@arndb.de>