arm64: dts: qcom: x1e80100-medion-sprchrgd-14-s1: correct firmware paths

arm64: dts: qcom: x1e80100-medion-sprchrgd-14-s1: correct firmware paths

Per the agreement, the firmware paths (even for devices not supported in
linux-firmware) should follow the SoC/Vendor/device pattern. Update
firmware names for Medion SPRCHRGD 14 S1 to follow that pattern.

Fixes: 8cf65490cdb0 ("arm64: dts: qcom: Add dts for Medion SPRCHRGD 14 S1")
Cc: Georg Gottleuber <ggo@tuxedocomputers.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20251224-fix-medion-v1-1-305747dff79a@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>