[NFC][clang] No sharedlibs for UEFI (#137872)

There is no support for shared libraries for UEFI target. Remove the
incorrect -dll flag set from UEFI toolchain.

Author: Prabhuk

clang/lib/Driver/ToolChains/UEFI.cpp

@@ -80,9 +80,6 @@ void tools::uefi::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   // "Terminal Service Aware" flag is not needed for UEFI applications.
   CmdArgs.push_back("-tsaware:no");
 
-  // EFI_APPLICATION to be linked as DLL by default.
-  CmdArgs.push_back("-dll");
-
   if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7))
     CmdArgs.push_back("-debug");
 

clang/test/Driver/uefi-constructed-args.c

@@ -11,5 +11,4 @@
 // CHECK-SAME: "-subsystem:efi_application"
 // CHECK-SAME: "-entry:EfiMain"
 // CHECK-SAME: "-tsaware:no"
-// CHECK-SAME: "-dll"
 // CHECK-SAME: "-debug"