Today, the eMMC on the omap5_uevm cannot be booted from, due to a bug in the save_boot_params function that tests for a range of XIP to MMC2. But in the case of OMAP5, MMC2 is eMMC boot partition and MMC2_2 is eMMC (main), and uEVM can only boot from MMC2_2. We cannot just update the test as-is because other platforms define away MMC2_2 to 0xFF as they cannot be passed that value. I've fixed this by making it clearer in the comments what we do, and use a platform definable variable to say where we must check the range for. This part has been tested on some relevant platforms for each case. While doing this, the question arose of how to partition eMMC (since u-boot must be written RAW and not put on FAT), so I've added GPT support for this. Finally, while in here I see we weren't using the fallbacks baud rate table, so I changed to that. This series will mildly conflict (mainly over the rename) with Sricharan's current series of fixes, so I shall resolve that.