This removes the headers imported from the embeddedsw repository in
favor of a much thinner shim. This also removes the complicated build
system configuration necessary to support use of these headers. The
primary reason for removal is that certain external Xilinx libraries
also require use of these headers and this causes version mismatches and
header conflicts that can be avoided.
This fixes build errors seen when building with console interrupts
enabled. A few places were missing bspopts.h includes, and one of the
UART functions was not defined.
