Revert "fastboot: add modules partition"

Revert submission 1413808-modules_partition

Reason for revert: modules partition no longer needed
Reverted Changes:
Iceafebd85:Add modules partition
I2fa96199a:rootdir: Add modules directory
Ie397b9ec6:Add modules partition.
I4200d0cf5:fastboot: add modules partition

Bug: 163543381

Change-Id: I17dc2da5a0901797c1bc1905274e7eb02e80fd83