docs: revert FVP versions for select models
docs: revert FVP versions for select models

Reverting FVP versions to previous version 11.12.38 for Cortex-A32x4
and Neoverse-N2x4.

Change-Id: I81e8ad24794dd425a9e9a66dc8bb02b42191abf1
Signed-off-by: Lauren Wehrmeister <c2872bb20a24754ba136deb455abb6add7d102f7@arm.com>

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware