kgdbts: mark kgdbts_option_setup() with __init to free init memory

kgdbts: mark kgdbts_option_setup() with __init to free init memory

The kgdbts_option_setup() function is invoked only once early in boot
via the __setup("kgdbts=", ...) mechanism to parse the kernel
command-line option.After init is complete, it is never called again.

Annotating it with __init places the function in the .init.text section,
enabling the kernel to free its code memory during the init memory
cleanup phase (free_initmem()). This reduces the kernel’s runtime
memory footprint with no functional side effects.

Signed-off-by: Can Peng <pengcan@kylinos.cn>
Link: https://patch.msgid.link/20251208130525.2775885-1-pengcan@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>