bloblist: Load the bloblist from the previous loader

During bloblist initialization, load the bloblist via boot arguments
from the previous loader.
If a valid bloblist exists in boot arguments, relocate it into the
fixed bloblist memory region.
If not, fallback to support BLOBLIST_ADDR or BLOBLIST_ALLOC.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>

include/bloblist.h

@@ -482,4 +482,14 @@ static inline int bloblist_maybe_init(void)
  */
 int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig);
 
+/**
+ * xferlist_from_boot_arg() - Get bloblist from the boot args and relocate it
+ *			      to the specified address.
+ *
+ * @addr: Address for the bloblist
+ * @size: Size of space reserved for the bloblist
+ * Return: 0 if OK, else on error
+ */
+int xferlist_from_boot_arg(ulong addr, ulong size);
+
 #endif /* __BLOBLIST_H */