staging: r8188eu: remove efuse write functions

The r8188eu driver in its current state does not need write access
to the efuses. Only read access is required to get the chip id, the
mac address and other settings.

This patch removes a lot of unused code for writing the efuses.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20211107161624.9452-3-martin@kaiser.cx


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