fix(qemu): fix register convention in BL31 for qemu

The commit with Change-Id:Ie417e054a7a4c192024a2679419e99efeded1705
updated the register convention r1/x1 values but missing necessary
changes in BL31.
As a result, a system panic observed during setup for BL32 when
TRANSFER_LIST is enabled due to unexpected arguments.
This patch is to fix this issue for qemu.

Change-Id: I42e581c5026f0f66d3b114204b4dff167a9bc6ae
Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
1 file changed