lib/scatterlist: Fix offset type in sg_alloc_table_from_pages

Scatterlist entries have an unsigned int for the offset so
correct the sg_alloc_table_from_pages function accordingly.

Since these are offsets withing a page, unsigned int is
wide enough.

Also converts callers which were using unsigned long locally
with the lower_32_bits annotation to make it explicitly
clear what is happening.

v2: Use offset_in_page. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Tomasz Stanislawski <t.stanislaws@samsung.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: linux-media@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com> (v1)
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170731185512.20010-1-tvrtko.ursulin@linux.intel.com

drivers/rapidio/devices/rio_mport_cdev.c

@@ -876,10 +876,10 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
 	 * offset within the internal buffer specified by handle parameter.
 	 */
 	if (xfer->loc_addr) {
-		unsigned long offset;
+		unsigned int offset;
 		long pinned;
 
-		offset = (unsigned long)(uintptr_t)xfer->loc_addr & ~PAGE_MASK;
+		offset = lower_32_bits(offset_in_page(xfer->loc_addr));
 		nr_pages = PAGE_ALIGN(xfer->length + offset) >> PAGE_SHIFT;
 
 		page_list = kmalloc_array(nr_pages,