iwlwifi: fix printk format warnings in uefi.c

The kernel test robot reports printk format warnings in uefi.c, so
correct them.

../drivers/net/wireless/intel/iwlwifi/fw/uefi.c: In function 'iwl_uefi_get_pnvm':
../drivers/net/wireless/intel/iwlwifi/fw/uefi.c:52:30: warning: format '%zd' expects argument of type 'signed size_t', but argument 7 has type 'long unsigned int' [-Wformat=]
   52 |                              "PNVM UEFI variable not found %d (len %zd)\n",
      |                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   53 |                              err, package_size);
      |                                   ~~~~~~~~~~~~
      |                                   |
      |                                   long unsigned int
../drivers/net/wireless/intel/iwlwifi/fw/uefi.c:59:29: warning: format '%zd' expects argument of type 'signed size_t', but argument 6 has type 'long unsigned int' [-Wformat=]
   59 |         IWL_DEBUG_FW(trans, "Read PNVM from UEFI with size %zd\n", package_size);
      |                             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  ~~~~~~~~~~~~
      |                                                                    |
      |                                                                    long unsigned int

Fixes: 84c3c995 ("iwlwifi: move UEFI code to a separate file")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Luca Coelho <luciano.coelho@intel.com>
Cc: linux-wireless@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210821020901.25901-1-rdunlap@infradead.org