ShellPkg\Tftp.c: Refine parameter name and use implicit comparison for BOOLEAN variable.

1. Refine parameter name to consistent with function headers.
2. To avoid potential bug BOOLEAN values should not use explicit comparisons to TRUE or FALSE.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qiu Shumin <shumin.qiu@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18222 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c

@@ -73,7 +73,7 @@ STATIC
 EFI_STATUS 
 GetNicName (
   IN   EFI_HANDLE  ControllerHandle,
-  IN   UINTN       Index,
+  IN   UINTN       NicNumber,
   OUT  CHAR16      *NicName
   );
 
@@ -524,7 +524,7 @@ ShellCommandRunTftp (
       );
   }
 
-  if ((UserNicName != NULL) && (NicFound == FALSE)) {
+  if ((UserNicName != NULL) && (!NicFound)) {
     ShellPrintHiiEx (
       -1, -1, NULL, STRING_TOKEN (STR_TFTP_ERR_NIC_NOT_FOUND),
       gShellTftpHiiHandle, UserNicName