ARM: dts: qcom: msm8974: Remove bogus cd-gpio pinctrl

No board in mainline uses GPIO 54 for card-detect on sdhc_2, and this
also causes conflict when both sdhc_2 and blsp2_uart4 are used, such as
on qcom-msm8974-lge-nexus5-hammerhead.

Fixes: 1dfe967e

 ("ARM: dts: qcom-msm8974*: Consolidate I2C/UART/SDHCI")
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20231217-msm8974-misc-v1-2-bece1ba2667d@z3ntu.xyz
Signed-off-by: Bjorn Andersson <andersson@kernel.org>