display5: Add missing environment.h include to avoid warning
Without this change the following warning shows up when building:
board/liebherr/display5/display5.c:270:3:
warning: implicit declaration of function ‘eth_env_set_enetaddr’ [-Wimplicit-function-declaration]
This commit fixes this issue.
Signed-off-by: Lukasz Majewski <lukma@denx.de>