With CONFIG_IWLWIFI_DEVICE_TRACING=y, these functions are rather large,
too big for inlining.

With this .config: http://busybox.net/~vda/kernel_config,
after uninlining these functions have sizes and callsite counts
as follows:

iwl_read32  475 bytes, 51 callsites
iwl_write32 477 bytes, 90 callsites
iwl_write8  493 bytes, 3 callsites

Reduction in size is about 74,000 bytes:

    text     data      bss       dec     hex filename
90758147 17226024 36659200 144643371 89f152b vmlinux0
90687995 17221928 36659200 144569123 89df323 vmlinux.after
Reported-by: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>