staging: rtl8192u: remove variable 'Ret' in r819xU_phy.c

This patch removes variable 'Ret' from rtl8192_QueryBBReg()
since its value is returned immediately after it is
assigned. The name 'Ret', anyway, does not give any
insight and the function description comment is sufficiently
informative regarding the returned value.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>