imx: imx_cntr_image.sh: prevent warning for missing spl

when building U-Boot on imx8qxp and the board port uses
SPL, U-boot build shows

WARNING '.../spl/u-boot-spl.bin' not found, resulting binary is not-functional

This is because U-Boot binary is build first and Makefile
calls script imx_cntr_image.sh which checks if files
exists... but of course as spl is not yet build the
file `spl/u-boot-spl.bin` does not exist yet, so prevent
this warning.

Signed-off-by: Heiko Schocher <hs@denx.de>
1 file changed