efi_loader: Enable RISCV_EFI_BOOT_PROTOCOL support

This adds support for new RISCV_EFI_BOOT_PROTOCOL to
communicate the boot hart ID to bootloader/kernel on RISC-V
UEFI platforms.

The specification of the protocol is hosted at:
https://github.com/riscv-non-isa/riscv-uefi

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

include/efi_api.h

@@ -438,6 +438,10 @@ struct efi_runtime_services {
 	EFI_GUID(0x607f766c, 0x7455, 0x42be, 0x93, \
 		 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
 
+#define RISCV_EFI_BOOT_PROTOCOL_GUID \
+	EFI_GUID(0xccd15fec, 0x6f73, 0x4eec, 0x83, \
+		 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)
+
 /**
  * struct efi_configuration_table - EFI Configuration Table
  *