dmaengine: stm32-dma3: restore channel semaphore status after suspend

dmaengine: stm32-dma3: restore channel semaphore status after suspend

Depending on the power state reached during suspend, the CxSEMCR register
could have been reset, and the semaphore released.
On resume, try to take the semaphore again. If the semaphore cannot be
taken, an error log displaying the channel number and channel user is
generated.

This requires introducing two new functions:
stm32_dma3_pm_suspend(), where the status of each channel is checked
because suspension is not allowed if a channel is still running;
stm32_dma3_pm_resume(), where the channel semaphore is restored if it was
taken before suspend.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://patch.msgid.link/20251121-dma3_improv-v2-3-76a207b13ea6@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>