Work around b/189992601: "SSE register cannot be used when SSE is disabled!"

The combination of -Xclang -msoft-float and -Xclang -no-implicit-float
causes Clang to assert. Since GRUB doesn't use floats, not passing
 -Xclang -msoft-float is a safe way to avoid this assert.
https://bugs.llvm.org/show_bug.cgi?id=48528 tracks fixing this on the
LLVM side, after which we won't need this patch anymore.

diff --git a/grub-2.02.old/configure.ac b/grub-2.02/configure.ac
index edd1841..3ec8008 100644
--- a/grub-2.02.old/configure.ac
+++ b/grub-2.02/configure.ac
@@ -811,9 +811,11 @@ if test x"$platform" != xemu ; then
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
 		         [grub_cv_target_cc_soft_float="-mno-inline-float-divide -mno-inline-sqrt"], [])
     fi
-    for cand in "-msoft-float -Xclang -msoft-float -Xclang -no-implicit-float" \
-		"-Xclang -msoft-float -Xclang -no-implicit-float" \
-		"-Xclang -msoft-float" "-msoft-float"; do
+    # b/189992601: "SSE register cannot be used when SSE is disabled!"
+    # if we use -Xclang -msoft-float and -Xclang -no-implicit-float.
+    # Since GRUB doesn't use any floating point, just -no-implicit-float
+    # should be enough.
+    for cand in "-Xclang -no-implicit-float"; do
       if test x"$grub_cv_target_cc_soft_float" != xno ; then
         break
       fi