powerpc/powernv/flash: Check OPAL flash calls exist before using

Currently only FSP based powernv systems supports firmware update
interfaces. Hence check that the token OPAL_FLASH_VALIDATE exists
before initalising the flash driver.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210914101630.30613-1-hegdevasant@linux.vnet.ibm.com

Author: Vasant Hegde

arch/powerpc/platforms/powernv/opal-flash.c

@@ -520,6 +520,10 @@ void __init opal_flash_update_init(void)
 {
 	int ret;
 
+	/* Firmware update is not supported by firmware */
+	if (!opal_check_token(OPAL_FLASH_VALIDATE))
+		return;
+
 	/* Allocate validate image buffer */
 	validate_flash_data.buf = kzalloc(VALIDATE_BUF_SIZE, GFP_KERNEL);
 	if (!validate_flash_data.buf) {