sparc64: /sys/firmware/efi missing during EFI boot

sparc64: /sys/firmware/efi missing during EFI boot

The newest version of OBP is capable of doing an EFI boot.  When Linux
is booted thru this EFI loader, the /sys/firmware/efi directory does
not exist.  Many userspace applications, such as GRUB, check whether
the dir /sys/firmware/efi exists, if it exists it means
the kernel has booted in EFI mode.

A new Open Firmware property called efi-booter has been added
to /chosen. This new property is only present when doing an
EFI boot.

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Reviewed-by Thomas Tai <thomas.tai@oracle.com>

Orabug: 26037358
Signed-off-by: Allen Pais <allen.pais@oracle.com>