staging: r8188eu: Remove unused macros

Simple variants of macros PlatformEFIOWrite and PlatformEFIORead are
defined but never used. As they do not appear to be designed for anything
significant, we can remove them to avoid unexpected usage.

Suggested-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Deepak R Varma <drv@mailo.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/efaf637a14b6f7fdd0178e2aecf8abf17e6922f6.1666299151.git.drv@mailo.com


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