most probably you simply do not have a hardware rng. I have an S3210SH, http://download.intel.com/support/motherboards/server/s3200sh/sb/e14960007_s3210sh_tps_r1_7.pdf , and reading that pdf I thought for hours that I have one. However, what it really says is that the BMC chip has one. I was able to access the BMC chip with the stock kernel modules (see http://buttersideup.com/docs/howto/IPMI_on_Debian.html ), but nothing indicates that the BMC exports the hwrng functionality, or at least nothing indicates that ipmitool gives an interface to access it.
The patch you linked in is already incorporated into the debian kernel you mention (I checked the code). Even the name of the parameter is the same:
# uname -r
# modinfo intel-rng | grep -A10 parm
parm:********** no_fwh_detect:Skip FWH detection:
*positive value - skip if FWH space locked read-only
*negative value - skip always (int)
So I think that the link you pointed out will not help, and the reason is very simple: our boards probably do not have a hwrng. Show me any indication whatsoever that I might have one, and I'll continue hunting it