Michael Brown
0d4a760ffc
[prefix] Use %cs as implicit parameter to uninstall()
romprefix.S currently calls uninstall() with an invalid value in %ax.
Consequently, base memory is not freed after a ROM boot attempt (or
after entering iPXE during POST).
The uninstall() function is physically present in .text16, and so can
use %cs to determine the .text16 segment address. The .data16 segment
address is not required, since uninstall() is called only by code
paths which set up .data16 to immediately follow .text16.
Signed-off-by: Michael Brown <mcb30@ipxe.org>