Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

Remove various 32-bit assumptions scattered throughout the codebase.
The code is still not necessarily 64-bit clean, but will at least
compile.

Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>

I want to get to the point where any header in include/ reflects a
standard user-level header (e.g. a POSIX header), while everything that's
specific to gPXE lives in include/gpxe/.  Headers that reflect a Linux
header (e.g. if_ether.h) should also be in include/gpxe/, with the same
name as the Linux header and, preferably, the same names used for the
definitions.

perl -pi -0777 -e 's/^(\s*)dev->disable(\s*)=\s*(\w+)_disable;\s*nic->poll\s*=\s*(\w+);\s*nic->transmit\s*=\s*(\w+);\s*nic->irq\s*=\s*(\w+);/static struct nic_operations ${3}_operations;\nstatic struct nic_operations ${3}_operations = {\n\t.connect\t= dummy_connect,\n\t.poll\t\t= $4,\n\t.transmit\t= $5,\n\t.irq\t\t= $6,\n\t.disable\t= ${3}_disable,\n};${1}nic->nic_op\t= &${3}_operations;/msg' *.c

perl -pi -0777 -e 's/_disable\s*\(\s*struct dev \*dev\s*\)\s*{\s*struct nic \*nic.*?$/_disable ( struct nic *nic ) {/ms' *.c

perl -pi -0777 -e 's/_disable\s*\(\s*struct dev \*dev(\s*__unused)?\)\s*{/_disable ( struct nic *nic$1 ) {/ms' *.c