FROMGIT: clk: mediatek: support COMMON_CLK_MEDIATEK module build

To support COMMON_CLK_MEDIATEK module build,
add MODULE_LICENSE and export necessary symbols.

Bug: 204842001
(cherry picked from commit 32b028fb
 https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git/

 clk-next)
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Hanks Chen <hanks.chen@mediatek.com>
Cc: Wendell Lin <wendell.lin@mediatek.com>
Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Link: https://lore.kernel.org/r/20210901222526.31065-3-miles.chen@mediatek.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Change-Id: I4784e3e82262b651b4ba7cc0a03f575f65b0d72e