firmware: cs_dsp: Validate payload length before processing block

In the Linux kernel, the following vulnerability has been resolved:

firmware: cs_dsp: Validate payload length before processing block

Move the payload length check in cs_dsp_load() and cs_dsp_coeff_load()

to be done before the block is processed.

The check that the length of a block payload does not exceed the number

of remaining bytes in the firwmware file buffer was being done near the

end of the loop iteration. However, some code before that check used the

length field without validating it.