patch 8.1.0733: too many #ifdefs for the multi-byte feature

Problem:    Too many #ifdefs for the multi-byte feature.
Solution:   Tentatively always enable the multi-byte feature.  If you have a
            problem with this, please discuss on the Vim maillist.
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index baf0b7d..0a92530 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -26,15 +26,13 @@
 #	GUI interface: GUI=yes (default is no)
 #
 #	GUI with DirectWrite (DirectX): DIRECTX=yes
-#	  (default is yes if GUI=yes, requires GUI=yes and MBYTE=yes)
+#	  (default is yes if GUI=yes, requires GUI=yes)
 #
 #	Color emoji support: COLOR_EMOJI=yes
 #	  (default is yes if DIRECTX=yes, requires WinSDK 8.1 or later.)
 #
 #	OLE interface: OLE=yes (usually with GUI=yes)
 #
-#	Multibyte support: MBYTE=yes (default is yes for NORMAL, BIG, HUGE)
-#
 #	IME support: IME=yes	(requires GUI=yes)
 #	  DYNAMIC_IME=[yes or no]  (to load the imm32.dll dynamically, default
 #	  is yes)
@@ -786,11 +784,6 @@
 !if "$(GIME)" == "yes"
 CFLAGS = $(CFLAGS) -DGLOBAL_IME
 OBJ = $(OBJ) $(OUTDIR)\dimm_i.obj $(OUTDIR)\glbl_ime.obj
-MBYTE = yes
-!endif
-
-!if "$(MBYTE)" == "yes"
-CFLAGS = $(CFLAGS) -DFEAT_MBYTE
 !endif
 
 !if "$(GUI)" == "yes"