crypto: stm32/cryp - fix bugs and crash in tests

Extra crypto manager auto test were crashing or failling due
to 2 reasons:
- block in a dead loop (dues to issues in cipher end process management)
- crash due to read/write unmapped memory (this crash was also reported
when using openssl afalg engine)

Rework interrupt management, interrupts are masked as soon as they are
no more used: if input buffer is fully consumed, "Input FIFO not full"
interrupt is masked and if output buffer is full, "Output FIFO not
empty" interrupt is masked.
And crypto request finish when input *and* outpout buffer are fully
read/write.

About the crash due to unmapped memory, using scatterwalk_copychunks()
that will map and copy each block fix the issue.
Using this api and copying full block will also fix unaligned data
access, avoid early copy of in/out buffer, and make useless the extra
alignment constraint.

Fixes: 9e054ec2 ("crypto: stm32 - Support for STM32 CRYP crypto module")
Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>