spi: stm32_qspi: migrate trace to dev and log macro

Change debug/pr_* to log_* or dev_* macro and define LOG_CATEGORY.

Remove the "%s:" __func__  header as it is managed by dev macro
(dev->name is displayed) or log macro (CONFIG_LOGF_FUNC).

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>