spi: stm32-ospi: Fix an IS_ERR() vs NULL bug in stm32_ospi_get_resources()

The devm_ioremap() function returns NULL on error, it doesn't return
error pointers.  Fix the check to match.

Fixes: 79b8a705 ("spi: stm32: Add OSPI driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Link: https://patch.msgid.link/bc4c9123-df43-4616-962f-765801d30b4c@stanley.mountain


Signed-off-by: Mark Brown <broonie@kernel.org>