platform/x86: asus-wmi: use brightness_set_blocking() for kbd led

platform/x86: asus-wmi: use brightness_set_blocking() for kbd led

[ Upstream commit ccb61a328321ba3f8567e350664c9ca7a42b6c70 ]

kbd_led_set() can sleep, and so may not be used as the brightness_set()
callback.

Otherwise using this led with a trigger leads to system hangs
accompanied by:
BUG: scheduling while atomic: acpi_fakekeyd/2588/0x00000003
CPU: 4 UID: 0 PID: 2588 Comm: acpi_fakekeyd Not tainted 6.17.9+deb14-amd64 #1 PREEMPT(lazy)  Debian 6.17.9-1
Hardware name: ASUSTeK COMPUTER INC. ASUS EXPERTBOOK B9403CVAR/B9403CVAR, BIOS B9403CVAR.311 12/24/2024
Call Trace:
 <TASK>
 [...]
 schedule_timeout+0xbd/0x100
 __down_common+0x175/0x290
 down_timeout+0x67/0x70
 acpi_os_wait_semaphore+0x57/0x90
 [...]
 asus_wmi_evaluate_method3+0x87/0x190 [asus_wmi]
 led_trigger_event+0x3f/0x60
 [...]

Fixes: 9fe44fc98ce4 ("platform/x86: asus-wmi: Simplify the keyboard brightness updating process")
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Denis Benato <benato.denis96@gmail.com>
Link: https://patch.msgid.link/20251129101307.18085-3-anton@khirnov.net
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>