In case no BOM is present in the CSV file the utf-16 codec won't work.
We fail over to utf-16-le as Little Endian is commonly used.
NOTE: The original change landed this fix in efi_utils.py, however
that was introduced after the Xena development cycle, so this
backport moves the original change to where the code originally
came from to populate the efi_utils.py file.
Change-Id: I3e25ce4997f5dd3df87caba753daced65838f85a
(cherry picked from commit 697fa6f3b6)
(cherry picked from commit 99b9d1403c)