staging: rtl8188eu: simplify loop in rtl88eu_phy_iq_calibrate()

Zeroing the array result[m][n] and setting only the values at
even 'n's simplifies the code and slightly reduces object file
size.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>