STM32: SPI 3 wires mode not supported in SPI slave

[LMESTM]

This patch handles the case of SPI slave mode without MISO (NC).
In case MISO is not connected, we consider that SPI will be configured in
3 wires mode (CLK / MOSI / CS, but no MISO). In this case, the MOSI line
is bi-directional : SPI_DIRECTION_1LINE.

But as this is not supported yet in slave mode, we force it to
SPI_DIRECTION_2LINES. In this case slave SPI will receive data on MOSI
but nothing will be sent back to master as MISO is not connected.

This FIX addresses the issue reported in: #5554

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 587
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/5565/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 199
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5565/

[mbed-ci]

Test : FAILURE

Build number : 400
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5565/400

[0xc0170]

nucleo f429 time-outs for sleep lock, this does not seem related, at least one more retrigger to be certain this is master/this patch issue.

/morph test

[mbed-ci]

Test : FAILURE

Build number : 412
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5565/412

[kegilbert]

F429ZI was failing with bad flashes, updated some of the CI hardware to hopefully resolve the issue. Will kick off the test again in a minute.

[kegilbert]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 425
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5565/425