9ba760e603
ask to map in oxpcie i/o memory and support serial i/o for it in the kernel. set oxpcie=<address> in boot monitor (retrieve address using pci_debug=1 output). (no sanity checking is done on the address currently.) disabled by default. The change also contains some other minor cleanup (a new serial.h to set register info common to UART and the OXPCIe card, in-kernel memory mapping a little more structured and env_get() to get sysenv variables without knowing about the params_buffer).