ramips: fix dts file name for SNR-CPE-ME1
Rename file mt7621_snr_snr-spe-me-1.dts
Fixes: #12562
Fixes: ecdb248 ("ramips: add support for SNR-CPE-ME1")
Tested-by: Rafał Miłecki <[email protected]>
Signed-off-by: Maximilian Weinmann <[email protected]>