swiotlb: Defer swiotlb init printing, export swiotlb_print_info()

This enables us to avoid printing swiotlb memory info when we
initialize swiotlb. After swiotlb initialization, we could find
that we don't need swiotlb.

This patch removes the code to print swiotlb memory info in
swiotlb_init() and exports the function to do that.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
Cc: muli@il.ibm.com
Cc: tony.luck@intel.com
Cc: benh@kernel.crashing.org
LKML-Reference: <1257849980-22640-9-git-send-email-fujita.tomonori@lab.ntt.co.jp>
[ -v2: merge up conflict ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>