soc: qcom: mdt_loader: Allow hash segment to be split out

It's been observed that some firmware found in a Qualcomm SM8450 device
has the hash table in a separate .bNN file. Use the newly extracted
helper function to load this segment from the separate file, if it's
determined that the hashes are not part of the already loaded firmware.

In order to do this, the function needs access to the firmware basename
and to provide more useful error messages a struct device to associate
the errors with.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>