spi: add non-blocking bus acquisition

[floitsch]

Adds an explicit non-blocking SPI bus-acquisition API for asynchronous runtimes. A failed try does not leave a pending lock request behind, while success has the same release contract as spi_device_acquire_bus.

This is needed by the stacked Toit asynchronous SPI controller change: primitives must never wait on an RTOS semaphore.

Validated through two-device Toit hardware tests on ESP32 and ESP32-S3, including repeated acquisition attempts while an interrupt-driven transaction owns the bus.

Stacked on #125.

[floitsch]

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📥 Commits

Reviewing files that changed from the base of the PR and between 0e068a0 and 9b402a6.

📒 Files selected for processing (4)

• components/esp_driver_spi/include/driver/spi_master.h
• components/esp_driver_spi/src/gpspi/spi_master.c
• components/esp_hw_support/include/esp_private/spi_share_hw_ctrl.h
• components/esp_hw_support/spi_bus_lock.c

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