fix(fb): fix pwm value calculation

[why]
the brightness turns off on raven as soon as it's turned down
[how]
calculate pwm value correctly (0xff * 0x101) as in linux

NootedRed/X6000FB.cpp

@@ -332,7 +332,7 @@ IOReturn X6000FB::wrapSetAttributeForConnection(IOService *framebuffer, IOIndex
             return kIOReturnSuccess;
         }
     } else {
-        UInt32 pwmValue = percentage >= 100 ? 0x1FF00 : ((percentage * 0xFF) / 100) << 8U;
+        UInt32 pwmValue = (percentage * 0xFFFF) / 100;
         DBGLOG("X6000FB", "setAttributeForConnection: New PWM brightness: 0x%X", pwmValue);
 
         if (callback->orgDcLinkSetBacklightLevel(callback->embeddedPanelLink, pwmValue, 0)) { return kIOReturnSuccess; }