Fixes #10739

boards/esp32-wroom-32: configure saul button as inverted

doxygen: refine grouping of kernel docs

cpu/esp32: cleanup in periph/spi

SPI0_DEV and SPI1_DEV configuration parameters are renamed SPI0_CTRL and SPI1_CTRL to better describe what they define and to avoid confusion with SPI_DEV (0) and SPI_DEV (1).

Although ESP32 has four SPI controllers, only two of them can be effectively used (HSP and VSPI). The third one (FSPI) is used for external memory such as flash and PSRAM and can not be used for peripherals. FSPI is therefore removed from the API. In addition, the SPI0_DEV and SPI1_DEV configuration parameters are renamed SPI0_CTRL and SPI1_CTRL to better describe what they define and to avoid confusion with SPI_DEV (0) and SPI_DEV (1).

Although ESP32 has four SPI controllers, only two of them can be effectively used (HSP and VSPI). The third one (FSPI) is used for external memory such as flash and PSRAM and can not be used for peripherals. FSPI is therefore removed from the API. In addition, the SPI0_DEV and SPI1_DEV configuration parameters are renamed SPI0_CTRL and SPI1_CTRL to better describe what they define and to avoid confusion with SPI_DEV (0) and SPI_DEV (1).

driver/enc28j60: cleanup

nanocoap: fix sock_udp return value checks

drivers/bmx055: eliminate some casts

- Move `@defgroup core_sync` group definition to doc.txt
- Adapt usage of `@ingroup core_sync` accordingly

gcoap/example: add comment on resource order

according to nanocoap/example: fix resource order #9919

First, every read function converts the void pointer into a const bmx055_t

Second, it is cleaner (more obvious) to pass phydat_t.val[3] instead of
type casting to int16_t* and relying that .val[3] is the first struct
member of phydat_t.

boards/esp32: UART configuration fix

drivers/cc2420: move flush sequence to inline function 

drivers: replace memset by simple assignments

cpu/stm32_common: add DMA support for all stm32

tests: remove NETOPT_IPV6_IID get() from driver_at86rf2xx test

drivers/bh1750fvi: change prototype of bh1750fvi_init

gnrc_ipv6_nib: fix RA reception for non-6LN interfaces

gnrc_sixlowpan_frag: unroll recursion

Used with UART and SPI peripheral