HW: Adjust the eMMC pull-ups

[jadonk]

I'm not sure if this is needed, but it is proposed for Rev A2:

[dcelectr]

According to the AM57xx Schematic Checklist, Section 2.12:
"For eMMC implementations, 47K-50K pull-up resistors are only needed on the first data signal (DAT0) and on the command signal. They are not required on the DAT7:DAT1 connections as these are provided within the eMMC device at start-up."
https://www.ti.com/lit/pdf/sprack7

According to the Kingston Embedded Multi-Media Card documentation for EMMC15G-TB29, page9:
"The eMMC device includes internal pull-ups for data lines DAT1-DAT7."
http://static6.arrow.com/aropdfconversion/600abac7089ab69d925e54c048b3013f15c7066d/kingston_emmc16g-tb29-pz90_2020-02-07_13-45-15.pdf

Thus, we can make R175 through R179, R184 and R185 "Not Installed".

We have the 22R (R202) series resistor on MMC2_CLK to eliminate possible signal reflections on the signal that can cause false clock transitions. However, I did not confirm if R202 is placed as close to the processor as possible.

The VDD_EMMC is connected to 1V8 through R702 (0R), and 1V8 for I/O would support maximum data bus throughput of 400 MB/s (Mode HS400).

All these are consistent with other eMMC related reference designs I have worked on.