flyingf3: add support for ms5611 baro on rcflyer shield
ms5611: only use minimal #includes for API
ms5611: allow SPI and I2C driver variants to coexist
flyingf3: support ms5611 on i2c on chebuzz shield
ms5611: formatting fixes

No functional changes.
ms5611_spi: port fixes from i2c driver variant
ms5611: scale delays by portTICK_RATE_MS
ms6511_spi: remove docs for obsolete return code
ms5611: fix forward declaration with empty parameter list
Merge pull request #700 from solidgoldbomb/ff3-ms5611-support

flyingf3: support ms5611 baro on rcflyer and chebuzz shields