ArmPkg: DebugPeCoffExtraActionLib: debugger commands are not errors

ArmPkg: DebugPeCoffExtraActionLib: debugger commands are not errors

In commit 1fce963d89f3e we reduced the level of information printed
by PeCoffLoaderRelocateImageExtraAction() but we did not update the
similar PeCoffLoaderUnloadImageExtraAction() function.

PeCoffLoaderUnloadImageExtraAction() prints helpful debugger commands
for source level debugging. These messages should not be printed on the
EFI_D_ERROR level; they don't report errors. Change the debug level
(bitmask, actually) to DEBUG_LOAD | DEBUG_INFO, because the messages are
printed in relation to image loading, and they are informative.

Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: Andrew Jones <drjones@redhat.com>
Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Philippe Mathieu-Daude <philmd@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>