firmware: bcm47xx_nvram: _really_ correct size_t printf format

Commit feb4eb060c ("firmware: bcm47xx_nvram: Correct size_t printf
format") was wrong, and changed a printout of 'header.len' - which is an
u32 type - to use '%zu'.

It apparently did pattern matching on the other case, where it printed
out 'nvram_len', which is indeed of type 'size_t'.

Rather than undoing the change, this just makes it use the variable that
the change seemed to expect to be used.

Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/firmware/broadcom/bcm47xx_nvram.c

@@ -149,7 +149,7 @@ static int nvram_init(void)
 		nvram_len = header.len;
 		if (nvram_len >= NVRAM_SPACE) {
 			pr_err("nvram on flash (%zu bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
-				header.len, NVRAM_SPACE);
+				nvram_len, NVRAM_SPACE);
 			nvram_len = NVRAM_SPACE - 1;
 		}