Due to a regression bug in #1741 the autonomous landing without GPS used manual RC
input to determine setpoints which broke auto landing without GPS.

Insure that CONFIG_ARCH_BOARD_xxx is defined and to be consistent with Nuttx build place them in defconfig files so that config.h will have ONFIG_ARCH_BOARD_xxx defined

EKF Fixes from @Zefz

HMC5883: Always report as internal sensor in SPI mode, since the sensor is fixed to the autopilot assembly.

sensors app: Use -1 in rotation parameter to indicate that a sensor cannot be rotated as it is internal.