platform/x86: thinkpad_acpi: remove obsolete TODO comment

This patch removes the obsolete TODO comment regarding fan speed
presets in fan_write_cmd_speed. After discussion with the
maintainers, it was decided that fixed presets (low/medium/high)
are not suitable due to platform-specific variations.

Signed-off-by: Daniil Bulgar <bulgardaniil18@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://patch.msgid.link/20260407190546.109900-1-bulgardaniil18@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: MEROWN

drivers/platform/x86/lenovo/thinkpad_acpi.c

@@ -9235,9 +9235,6 @@ static int fan_write_cmd_speed(const char *cmd, int *rc)
 {
 	int speed;
 
-	/* TODO:
-	 * Support speed <low> <medium> <high> ? */
-
 	if (sscanf(cmd, "speed %d", &speed) != 1)
 		return 0;