mmc: core: sd: implement proper support for sd3.0 au sizes

This reverts and updates commit 77776fd0a4cc541b9 ("mmc: sd: fix the
maximum au_size for SD3.0"). The au_size for SD3.0 cannot be achieved
by a simple bit shift, so this needs to be implemented differently.
Also, don't print the warning in case of 0 since 'not defined' is
different from 'invalid'.

Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: stable <stable@vger.kernel.org> # [3.12, 3.13]
Signed-off-by: Chris Ball <chris@printf.net>
Git-commit: 9288cac05405a7da406097a44721aa4004609b4d
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Change-Id: Ia19e30f1b9d793e1757a3eb3126b994df6b7a72a
[stummala@codeaurora.org: resolved merge conflicts]
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>