Added explicit attribute masks to the device mode demos' descriptors.

Bootloaders/CDC/Descriptors.c

Bootloaders/TeensyHID/Descriptors.c

Demos/Device/ClassDriver/CDC/Descriptors.c

Demos/Device/ClassDriver/DualCDC/Descriptors.c

Demos/Device/ClassDriver/GenericHID/Descriptors.c

Demos/Device/ClassDriver/Joystick/Descriptors.c

Demos/Device/ClassDriver/Keyboard/Descriptors.c

Demos/Device/ClassDriver/KeyboardMouse/Descriptors.c

Demos/Device/ClassDriver/MassStorage/Descriptors.c

Demos/Device/ClassDriver/Mouse/Descriptors.c

Demos/Device/ClassDriver/RNDISEthernet/Descriptors.c

Demos/Device/ClassDriver/USBtoSerial/Descriptors.c

Demos/Device/LowLevel/CDC/Descriptors.c

Demos/Device/LowLevel/DualCDC/Descriptors.c

Demos/Device/LowLevel/GenericHID/Descriptors.c

Demos/Device/LowLevel/Joystick/Descriptors.c

Demos/Device/LowLevel/Keyboard/Descriptors.c

Demos/Device/LowLevel/KeyboardMouse/Descriptors.c

Demos/Device/LowLevel/MassStorage/Descriptors.c

Demos/Device/LowLevel/Mouse/Descriptors.c