utils/genrandconfig: add ti-k3-r5-loader handling

Fix the following build failure raised since the addition of the package
in commit 0189bcb47c7733c36fcbcb88fbf26f57958db576:

make[2]: *** No rule to make target '_defconfig'.  Stop.

Fixes:
 - http://autobuild.buildroot.org/results/d7449b2b2f2349af672bfeee832b89a223a7d9cc

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

utils/genrandconfig

@@ -519,6 +519,11 @@ def fixup_config(sysinfo, configfile):
         configlines.remove('BR2_TARGET_S500_BOOTLOADER=y\n')
         configlines.remove('BR2_TARGET_S500_BOOTLOADER_BOARD=""\n')
 
+    if 'BR2_TARGET_TI_K3_R5_LOADER=y\n' in configlines and \
+       'BR2_TARGET_TI_K3_R5_LOADER_USE_DEFCONFIG=y\n' in configlines and \
+       'BR2_TARGET_TI_K3_R5_LOADER_BOARD_DEFCONFIG=""\n' in configlines:
+        return False
+
     if 'BR2_TARGET_UBOOT=y\n' in configlines and \
        'BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y\n' in configlines and \
        'BR2_TARGET_UBOOT_USE_CUSTOM_CONFIG=y\n' in configlines and \