Remove HAL_CHIBIOS_ARCH_FMUV4

[peterbarker]

Pixracer and luminousbee4 already define everything they need to define; they don't need an architecture and detection and whatnot.

All sensors that were on the board still are:

BARO1_DEVID: bus_type:SPI(2)  bus:2 address:3(0x3) devtype:11(0xb) BARO_MS5611 (721682)
COMPASS_DEV_ID: bus_type:SPI(2)  bus:1 address:5(0x5) devtype:7(0x7) HMC5883 (460042)
COMPASS_DEV_ID2: bus_type:SPI(2)  bus:1 address:4(0x4) devtype:4(0x4) AK8963  (263178)
COMPASS_PRIO1_ID: bus_type:SPI(2)  bus:1 address:5(0x5) devtype:7(0x7) HMC5883 (460042)
COMPASS_PRIO2_ID: bus_type:SPI(2)  bus:1 address:4(0x4) devtype:4(0x4) AK8963  (263178)
INS_GYR_ID: bus_type:SPI(2)  bus:1 address:6(0x6) devtype:33(0x21) GYR_MPU6000 (2164234)
INS_GYR2_ID: bus_type:SPI(2)  bus:1 address:4(0x4) devtype:36(0x24) GYR_MPU9250 (2360330)
INS_ACC_ID: bus_type:SPI(2)  bus:1 address:6(0x6) devtype:19(0x13) ACC_MPU6000 (1246730)
INS_ACC2_ID: bus_type:SPI(2)  bus:1 address:4(0x4) devtype:22(0x16) ACC_MPU9250 (1442826)

(I've obviously built and flashed Pixracer...)

No features have been lost on the boards:

pbarker@crun:~/rc/ardupilot(master)$ diff -u /tmp/master.txt /tmp/new.txt 
pbarker@crun:~/rc/ardupilot(master)$ 

Board                    AP_Periph  blimp  bootloader  copter  heli  iofirmware  plane  rover  sub
CubeOrange-periph-heavy  *                 *
CubeRedPrimary                      24     *           24      24                24     24     24
Durandal                            24     *           24      24                24     24     24
Hitec-Airspeed           *                 *
KakuteH7-bdshot                     *      *           *       *                 *      *      *
MatekF405                           *      *           *       *                 *      *      *
Pixhawk1-1M-bdshot                  24                 24      24                24     24     24
Pixracer                            -824   *           -848    -848              -840   -840   -880
f103-QiotekPeriph        *                 *
f303-Universal           *                 *
iomcu                                                                *
luminousbee4                        -968               -992    -992              -992   -992   -1040
revo-mini                           *      *           *       *                 *      *      *
skyviper-journey                                       *
skyviper-v2450                                         24

Optimisation can sometimes suck. We'll get those bytes back somehow :-)

[peterbarker]

Tested sensor orientation here. No change in behaviour - I'd be surprised if there were as this PR doesn't go near sensors.