firmware: bcm47xx_nvram: Correct size_t printf format
When building on a 64-bit host, we will get warnings like those:
drivers/firmware/broadcom/bcm47xx_nvram.c:103:3: note: in expansion of macro 'pr_err'
pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
^~~~~~
drivers/firmware/broadcom/bcm47xx_nvram.c:103:28: note: format string is defined here
pr_err("nvram on flash (%i bytes) is bigger than the reserved space in memory, will just copy the first %i bytes\n",
~^
%li