efi: efi-stub: notify on DTB absence

In the absence of a DTB configuration table, the EFI stub will happily
continue attempting to boot a kernel, despite the fact that this kernel
may not function without a description of the hardware. In this case, as
with a typo'd "dtb=" option (e.g. "dbt=") or many other possible
failures, the only output seen by the user will be the rather terse
output from the EFI stub:

EFI stub: Booting Linux Kernel...

To aid those attempting to debug such failures, this patch adds a notice
when no DTB is found, making the output more helpful:

EFI stub: Booting Linux Kernel...
EFI stub: Generating empty DTB

Additionally, a positive acknowledgement is added when a user-specified
DTB is in use:

EFI stub: Booting Linux Kernel...
EFI stub: Using DTB from command line

Similarly, a positive acknowledgement is added when a DTB from a
configuration table is in use:

EFI stub: Booting Linux Kernel...
EFI stub: Using DTB from configuration table

Signed-off-by: Mark Rutland <[email protected]>
Acked-by: Leif Lindholm <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Acked-by: Roy Franz <[email protected]>
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: Ard Biesheuvel <[email protected]>

0 files changed, 0 insertions, 0 deletions