RDL generated header uses 32-bit array type when memwidth is 64

[raylau1]

The auto generated RDL header uses uint32_t for memories with memwidth of 64. This causes assertion errors when running clang_tidy.

An example RDL and header with this issue can be found on branch ethernet_rdl.

[ziuziakowska]

Should be fixed by #579. I've also added your Ethernet RDL to that PR.