CR50: Include NUL byte from label for OAEP pad calculation
CR50: Include NUL byte from label for OAEP pad calculation

If a label is specified, then the NUL terminating
character is considered part of the label per the
TPM2 implementation.

BRANCH=none
BUG=chrome-os-partner:43025,chrome-os-partner:47524
TEST=tests under test/tpm2/ pass.

Change-Id: If5fccc293f7ab52fd6c33e2f3c38695c2921d919
Signed-off-by: nagendra modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Reviewed-on: https://chromium-review.googlesource.com/326910
Commit-Ready: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Tested-by: Marius Schilder <d423f2980be0298efdef7df239b147d21d472f26@chromium.org>
Tested-by: Nagendra Modadugu <5dc366ddbf8fb5981f46478e8436ef712a08b71b@google.com>
Reviewed-by: Marius Schilder <d423f2980be0298efdef7df239b147d21d472f26@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec