ARM: dts: ux500: Fix LCDA clock line muxing

[ Upstream commit ecde29569e3484e1d0a032bf4074449bce4d4a03 ]

The "lcdaclk_b_1" group is muxed with the function "lcd"
but needs a separate entry to be muxed in with "lcda"
rather than "lcd".

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>