wl1271: fix compiler warnings on 64 bit archs

There were a few warnings when compiling the wl1271 driver on 64 bit
architectures.  This was due to size mismatch of integers.

This commit fixes the following warnings:

drivers/net/wireless/wl12xx/wl1271_main.c: In function 'wl1271_irq_work':
drivers/net/wireless/wl12xx/wl1271_main.c:184: warning: large integer implicitly truncated to unsigned type
drivers/net/wireless/wl12xx/wl1271_boot.c: In function 'wl1271_boot_upload_firmware_chunk':
drivers/net/wireless/wl12xx/wl1271_boot.c:103: warning: format '%d' expects type 'int', but argument 2 has type 'size_t'
drivers/net/wireless/wl12xx/wl1271_boot.c:150: warning: format '%d' expects type 'int', but argument 2 has type 'size_t'
drivers/net/wireless/wl12xx/wl1271_boot.c: In function 'wl1271_boot_enable_interrupts':
drivers/net/wireless/wl12xx/wl1271_boot.c:278: warning: large integer implicitly truncated to unsigned type

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>