thinkpad-acpi: fix brightness hotkey poll handling
thinkpad-acpi: fix brightness hotkey poll handling

Handle multiple brightness hotkey presses between two polling cycles.

Signed-off-by: Henrique de Moraes Holschuh <1416ae054606eb9be8fa0d7696a4ddff667a3601@hmh.eng.br>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas