BaseTools/Conf: Don't support upper case nasm extensions

For *.asm and *.s, there have been cases of *.Asm and *.S files, but
since the nasm extensions are new, we don't need to support the upper
case extensions.

In other words, remove .Nasm and .NASM.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17544 6f19259b-4bc3-4df7-8a09-765794883524

BaseTools/Conf/build_rule.template

@@ -194,7 +194,7 @@
 
 [Nasm-Assembly-Code-File.COMMON.COMMON]
     <InputFile>
-        ?.nasm, ?.Nasm, ?.NASM
+        ?.nasm
 
     <ExtraDependency>
         $(MAKE_FILE)
@@ -479,7 +479,7 @@
 
 [Nasm-to-Binary-Code-File]
     <InputFile>
-        ?.nasmb, ?.NASMB
+        ?.nasmb
 
     <ExtraDependency>
         $(MAKE_FILE)