staging: r8188eu: clean up the blink worker code

Merge the BlinkWorkItemCallback and BlinkHandler functions.
Rename the resulting function to blink_work and make it
internal to the led layer.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20211226195556.159471-8-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>