efi_support: drop BIOS-mode info

Absence of an EFI runtime does not prevent loading efivarfs since commit
301de9a2055357375a4e1053d9df0f8f3467ff00 which landed in Linux v6.3.

Thus our check code cannot work anymore, and the message is at best misleading.

Author: zeha

grml-debootstrap

@@ -976,21 +976,17 @@ format_efi_partition() {
 
 # check for EFI support or try to enable it {{{
 efi_support() {
-  local efivars_loaded=false
-  if modprobe efivarfs &>/dev/null ; then
-    efivars_loaded=true
-  fi
+  # Absence of an EFI runtime does not prevent loading efivarfs since commit
+  # 301de9a2055357375a4e1053d9df0f8f3467ff00 which landed in Linux v6.3.
+  # Unconditionally load it, in case nothing else attempted it.
+  modprobe efivarfs &>/dev/null || true
 
   if [ -d /sys/firmware/efi ] ; then
     einfo "EFI support detected."
     return 0
   fi
 
-  if ! [ -d /sys/firmware/efi ] && [ "${efivars_loaded:-}" = "true" ] ; then
-    einfo "EFI support detected, but system seems to be running in BIOS mode."
-  fi
-
-  # The user may have a legitimate reason to do an EFI installation on a BIOS
+  # The user may have a legitimate reason to do an EFI installation on a non-EFI
   # system (for instance if doing a hybrid-bootable installation), so don't
   # return 1 here.
 }