u-boot: v2026.04: helios64: add ensure_otp_data_ready() to get_variant()

get_variant() was the only public OTP accessor that read the otp struct
without first validating/loading the cache. After a transient SPI failure
during board_early_init_r(), it could return a misleading variant string
from stale/partial data instead of exercising the retry path that
set_board_info() and mac_read_from_otp() already use.

Also make var_str static const — it's a read-only lookup table that
doesn't need to be rebuilt on every call.

Suggested-by: coderabbitai[bot]

Author: iav

patch/u-boot/v2026.04/board_helios64/board/sys_otp.c

@@ -229,15 +229,18 @@ int get_revision(int *major, int *minor)
 
 const char *get_variant(void)
 {
-	const char* var_str[BOARD_VARIANT_MAX] = {
+	static const char * const var_str[BOARD_VARIANT_MAX] = {
 		"Unknown",
 		"Engineering Sample",
 		"4GB non ECC"
 	};
 
+	if (ensure_otp_data_ready())
+		return var_str[BOARD_VARIANT_INVALID];
+
 	if ((otp.variant < BOARD_VARIANT_ENG_SAMPLE) ||
 		(otp.variant >= BOARD_VARIANT_MAX))
-		return var_str[0];
+		return var_str[BOARD_VARIANT_INVALID];
 
 	return var_str[otp.variant];
 }