arm64: dts: qcom: msm8998-mtp: Increase load on l21 for sdcard

l21 is used as sdcard vmmc, and needs the load increased to prevent
voltage drop issues with some sdcards.  This addresses -84 errors seen
during sdcard init with SDR104 cards.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>