EmbeddedPkg/Lan9118Dxe: Add or fix input parameter checks

EmbeddedPkg/Lan9118Dxe: Add or fix input parameter checks

Add or fix checking of the input parameters of the functions that constitute
the EFI_SIMPLE_NETWORK_PROTOCOL interface provided by the LAN9118 driver.
In case of invalid calls, the returned error codes are now compliant with the
UEFI specificationi and the SCT tests checking for those error codes do not
fail anymore.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ronald Cron <ronald.cron@arm.com>
Reviewed-By: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16239 6f19259b-4bc3-4df7-8a09-765794883524