uboot-imx

ARM: zynq: Guard zynq_help_text with CONFIG_SYS_LONGHELP

If SYS_LONGHELP is disabled the following warning is generated:
board/xilinx/zynq/cmds.c:496:13: warning: ‘zynq_help_text’ defined but
not used [-Wunused-variable]

Normal way for fixing this is to guard the whole variable.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>