trusty-ipc: fix return value on error path

If the transfer type is invalid, the call would incorrectly return 0
rather than an error code.

Bug: 400326085
Test: Treehugger
Change-Id: I7ae1a31c2ad09e7e682de133e0c144c43f96b7c8
Signed-off-by: Mike McTernan <[email protected]>
1 file changed