clk: ux500: Remove BML8580 clock

There is no mention of the PRCMU_BML8580CLK in any of the Design
Specifications for the chips supported in Mainline. In fact, where it
is incorrectly used in the u8540 clock definition driver it would
have the side effect of using the incorrect clock management address
([PRCM_BML8580CLK_MGT] 0x108 instead of the correct value 0x04C).

Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>