modpost: use snprintf() instead of sprintf() for safety

modpost: use snprintf() instead of sprintf() for safety

Use snprintf() to avoid the potential buffer overflow, and also
check the return value to detect the too long path.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>