kernel: fitimage: Repair misuse of shell test command
The kernel fitImage must be amended with signature if and only if
UBOOT_SIGN_ENABLE = 1 . In the current case, the UBOOT_SIGN_ENABLE
could be either 0 (default) or 1 , which test -n always correctly
interprets as non-empty string, thus always true. This does not
match the logic above though, so replace the test with check which
passes only for UBOOT_SIGN_ENABLE = 1 .
Signed-off-by: Marek Vasut <marex@denx.de> Cc: Yannick Gicquel <yannick.gicquel@iot.bzh> Cc: Richard Purdie <richard.purdie@linuxfoundation.org> Signed-off-by: Ross Burton <ross.burton@intel.com>
