spi: stm32h7: don't wait for EOT and flush fifo on disable

spi: stm32h7: don't wait for EOT and flush fifo on disable

In nominal cases, disable is called as part of the unprepare_message,
after receiving a EOT and after receiving all data so it doesn't
make sense to check for EOT and empty the FIFO.
Moreover, at the end of the disable, the SPI is disable (SPE) leading
to clear of all internal FIFO, leaving the IP in a known status.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1625646426-5826-7-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>