iwl: fix debug printf format strings

The variable 'package_size' is an unsigned long, and should be printed
out using '%lu', not '%zd' (that would be for a size_t).

Yes, on many architectures (including x86-64), 'size_t' is in fact the
same type as 'long', but that's a fairly random architecture definition,
and on some platforms 'size_t' is in fact 'int' rather than 'long'.

That is the case on traditional 32-bit x86.  Yes, both types are the
exact same 32-bit size, and it would all print out perfectly correctly,
but '%zd' ends up still being wrong.

And we can't make 'package_size' be a 'size_t', because we get the
actual value using efivar_entry_get() that takes a pointer to an
'unsigned long'.  So '%lu' it is.

This fixes two of the i386 allmodconfig build warnings (that is now an
error due to -Werror).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>