All others are initialized this way.

   This is a back port of upstream NuttX PX4 contrib of

   ef42c25 stm32f7:SDMMC add dcache alignment check in dma{recv|send}setup
                   In the where CONFIG_SDIO_PREFLIGHT is not used and dcache
                   write-buffed mode is used (not write-through) buffer alignment
                   is required for DMA transfers because a) arch_invalidate_dcache
                   could lose buffered writes data and b) arch_flush_dcache could
                   corrupt adjacent memory if the buffer and the bufflen, are not on
                   ARMV7M_DCACHE_LINESIZE boundaries.

   1e7ddfe  stm32f7:SDMMC remove widebus limitation on DMA
                    There is no documantation for the STM32F7 that limits DMA on
                    1 bit vrs 4 bit mode.

   dffab2f  stm32f7:DMA add dcache alignment check in stm32_dmacapable
                    In the case dcache write-buffed mode is used (not write-through)
                    buffer alignment is required for DMA transfers because
                    a) arch_invalidate_dcache could lose buffered writes data and
                    b) arch_flush_dcache could corrupt adjacent memory if the
                    maddr and the mend+1, the next next address are not on
                    ARMV7M_DCACHE_LINESIZE boundaries.

   38cbf1f  stm32f7:DMA correct comments and document stm32_dmacapable
            Updated comment to proper refernce manual for STM32F7 not STM32F4.
            Added stm32_dmacapable input paramaters documentation.

The code was violating the rule 'every successfull poll must be followed
by an orb_copy'.
The result was a busy loop.

 - change a little bit to make the code more readable

This is needed when logger is logging to file and ulog streaming gets
activated.

hardfault_store_filename() opens and closes a file descriptor, so if we do
it before opening the log file, we need one file descriptor less

This reduces the maximum number of needed file descriptors by 1 when using
ulog streaming.

This improves the printfs which will be logged. This should improve to
debug the camera triggering. The debug printfs are disabled by default.