AP_NavEKF3: tidy getPosNE

[peterbarker]

avoid deep indenting, it is actually a relatively straight-forward function

[peterbarker]

Board                    AP_Periph  blimp  bootloader  copter  heli  iofirmware  plane  rover  sub
CubeOrange-periph-heavy  *                                                                     
CubeRedPrimary                      0      *           0       0                 0      0      0
Durandal                            0      *           0       0                 0      0      0
Hitec-Airspeed           *                                                                     
KakuteH7-bdshot                     0      *           0       0                 0      0      0
MatekF405                           0      *           0       0                 0      0      0
Pixhawk1-1M-bdshot                  0                  0       0                 0      0      0
f103-QiotekPeriph        *                                                                     
f303-Universal           *                                                                     
iomcu                                                                *                         
revo-mini                           0      *           0       0                 0      0      0
skyviper-v2450                                         0