This function is evaluated during parse and some machines maynot use
external payload, on such machines this fails to parse
Fixes
bb.data_smart.ExpansionError: Failure expanding variable do_compile[depends], expression was ${@riscv_get_do_compile_depends(d)} which triggered exception TypeError: argument of type 'NoneType' is not iterab
le
Signed-off-by: Khem Raj <raj.khem@gmail.com> Cc: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
