MdePkg/Library/BaseLib: Enable VS2017/ARM builds

Most of the RVCT assembly can be reused as is for MSFT except
for CpuBreakpoint.asm, which we need to force to Arm mode.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Library/BaseLib/Arm/CpuBreakpoint.asm

@@ -16,7 +16,10 @@
 
     EXPORT CpuBreakpoint
 
-  AREA Cpu_Breakpoint, CODE, READONLY
+; Force ARM mode for this section, as MSFT assembler defaults to THUMB
+  AREA Cpu_Breakpoint, CODE, READONLY, ARM
+
+  ARM
 
 ;/**
 ;  Generates a breakpoint on the CPU.