pico-imx6ul: Select CONFIG_HUSH_PARSER option

Select CONFIG_HUSH_PARSER option in order to fix the following
problem:

Unknown command 'if' - try 'help'
Unknown command 'then' - try 'help'
Unknown command 'else' - try 'help'
Unknown command 'fi' - try 'help'

Reported-by: Daiane Angolini <daiane.angolini@nxp.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Daiane Angolini <daiane.angolini@nxp.com>

configs/pico-imx6ul_defconfig

@@ -2,6 +2,7 @@ CONFIG_ARM=y
 CONFIG_ARCH_MX6=y
 CONFIG_TARGET_PICO_IMX6UL=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/technexion/pico-imx6ul/imximage.cfg"
+CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_MEMTEST=y