lmb: change the return code on lmb_alloc_addr()

Ben reports a failure to boot the kernel on hardware that starts its
physical memory from 0x0.
The reason is that lmb_alloc_addr(), which is supposed to reserve a
specific address, takes the address as the first argument, but then also
returns the address for success or failure and treats 0 as a failure.

Since we already know the address change the prototype to return an int.

Reported-by: Ben Schneider <ben@bens.haus>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ben Schneider <ben@bens.haus>
Reviewed-by: Sughosh Ganu <sughosh.ganu@linaro.org>
diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index 6d00b18..c39b539 100644
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -491,8 +491,7 @@
 			return EFI_NOT_FOUND;
 
 		addr = map_to_sysmem((void *)(uintptr_t)*memory);
-		addr = (u64)lmb_alloc_addr(addr, len, flags);
-		if (!addr)
+		if (lmb_alloc_addr(addr, len, flags))
 			return EFI_NOT_FOUND;
 		break;
 	default: