zephyr: Fix BUILD_ASSERT failing build with correct number of images

Fix removes the unneeded BUILD_ASSERT.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>
diff --git a/cmd/img_mgmt/include/img_mgmt/img_mgmt_config.h b/cmd/img_mgmt/include/img_mgmt/img_mgmt_config.h
index 1a0b1cd..ee0343a 100644
--- a/cmd/img_mgmt/include/img_mgmt/img_mgmt_config.h
+++ b/cmd/img_mgmt/include/img_mgmt/img_mgmt_config.h
@@ -42,7 +42,6 @@
 #define IMG_MGMT_BOOT_CURR_SLOT 0
 #ifdef CONFIG_IMG_MGMT_UPDATABLE_IMAGE_NUMBER
 /* Up to two images are supported */
-BUILD_ASSERT(CONFIG_IMG_MGMT_UPDATABLE_IMAGE_NUMBER > 2, "Unsupported number of images");
 #undef IMG_MGMT_UPDATABLE_IMAGE_NUMBER
 #define IMG_MGMT_UPDATABLE_IMAGE_NUMBER CONFIG_IMG_MGMT_UPDATABLE_IMAGE_NUMBER
 #endif