Removed some of the XXX_reg macros now that we are using the standard
CONTEXT86 structure everywhere.

diff --git a/msdos/int15.c b/msdos/int15.c
index 6230fe1..7d72437 100644
--- a/msdos/int15.c
+++ b/msdos/int15.c
@@ -49,9 +49,9 @@
 
     case 0xc0: /* GET CONFIGURATION */
         if (ISV86(context)) /* real */
-            ES_reg(context) = 0xf000;
+            context->SegEs = 0xf000;
         else
-            ES_reg(context) = DOSMEM_BiosSysSeg;
+            context->SegEs = DOSMEM_BiosSysSeg;
         BX_reg(context) = 0xe6f5;
         AH_reg(context) = 0x0;
         RESET_CFLAG(context);