efi_loader: efi_console: use helper functions

efi_loader: efi_console: use helper functions

Use helper functions efi_created_handle and efi_add_protocol
for creating the console handles and instaling the respective
protocols.

This change is needed if we want to move from an array of
protocols to a linked list of protocols.

Eliminate EFI_PROTOCOL_OBJECT which is not used anymore.

Currently we have not defined protocol interfaces to be const.
So efi_con_out and efi_console_control cannot be defined as const.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>