configs/visionfive2: uboot needs openssl

The defconfig fails in uboot build, with output:

    scripts/sign-file.c:25:10: fatal error: openssl/opensslv.h: No such file or directory
       25 | #include <openssl/opensslv.h>
          |          ^~~~~~~~~~~~~~~~~~~~

This commit fixes the issue by adding
BR2_TARGET_UBOOT_NEEDS_OPENSSL=y to the defconfig.

Fixes:
- https://gitlab.com/buildroot.org/buildroot/-/jobs/6929002318

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/visionfive2_defconfig

@@ -30,6 +30,7 @@ BR2_TARGET_UBOOT_BOARD_DEFCONFIG="starfive_visionfive2"
 BR2_TARGET_UBOOT_NEEDS_DTC=y
 BR2_TARGET_UBOOT_NEEDS_PYLIBFDT=y
 BR2_TARGET_UBOOT_NEEDS_OPENSBI=y
+BR2_TARGET_UBOOT_NEEDS_OPENSSL=y
 # BR2_TARGET_UBOOT_FORMAT_BIN is not set
 BR2_TARGET_UBOOT_FORMAT_CUSTOM=y
 BR2_TARGET_UBOOT_FORMAT_CUSTOM_NAME="u-boot.itb"