efi_loader: add EFI_MEMORY_SP to memory attributes

The UEFI 2.8 specification has introduced the EFI_MEMORY_SP memory
attribute. Add it to the 'efidebug memmap' and 'efi mem' commands.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/cmd/efidebug.c b/cmd/efidebug.c
index 703dab0..32430e6 100644
--- a/cmd/efidebug.c
+++ b/cmd/efidebug.c
@@ -414,6 +414,7 @@
 	{EFI_MEMORY_NV, "NV"},
 	{EFI_MEMORY_MORE_RELIABLE, "REL"},
 	{EFI_MEMORY_RO, "RO"},
+	{EFI_MEMORY_SP, "SP"},
 	{EFI_MEMORY_RUNTIME, "RT"},
 };