tests: subsys: modem: backend: uart: stm32: fix dma DTS phandle lists

Correct b_u585i_iot02a board DTS overlay file DMA lists that was not
split by phandle and seemed to form a unique phandle. This is not
currently an issue with existing DT parsing macros and tools but may
generate build errors if tools are more strict on the DTS implementation
format.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
1 file changed