build: rename CONFIG_QGA_NTDDDISK to CONFIG_QGA_NTDDSCSI

There was inconsistency between commits:

  50cbebb9 configure: add configure check for ntdddisk.h
  a3ef3b22 qga: added bus type and disk location path

The first commit added #define CONFIG_QGA_NTDDDISK but the second commit
expected the name to be CONFIG_QGA_NTDDSCSI. As a result the code in
second patch was never used.

Renaming the option to CONFIG_QGA_NTDDSCSI to match the name of header
file that is being checked for.
Signed-off-by: NTomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NSameeh Jubran <sjubran@redhat.com>
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

configure

@@ -6142,7 +6142,7 @@ if test "$mingw32" = "yes" ; then
     echo "WIN_SDK=\"$win_sdk\"" >> $config_host_mak
   fi
   if test "$guest_agent_ntddscsi" = "yes" ; then
-    echo "CONFIG_QGA_NTDDDISK=y" >> $config_host_mak
+    echo "CONFIG_QGA_NTDDSCSI=y" >> $config_host_mak
   fi
   if test "$guest_agent_msi" = "yes"; then
     echo "QEMU_GA_MSI_ENABLED=yes" >> $config_host_mak