The issue is due to the SD Card not having a valid patition table. The easy solution is to create a valid patition table on SD Card. I did it as below.
1. Mount GParted (Live CD ISO) using KVM media mapper.
2. Delete any existing partition on SD Card.
3. Create a new Partition Table and set type to msdos
4. Create a new Primary Partition and set type to fat32
5. Apply changes and reboot using ESXi installation media. You will not see this error again.
You can probably do the above steps using any linux distribution.
Hope this helps.
