cxl: Remove function write_timebase_ctrl_psl9() for PSL9

cxl: Remove function write_timebase_ctrl_psl9() for PSL9

For PSL9 the contents of PSL_TB_CTLSTAT register have changed in PSL9
and all of the register is now readonly. Hence we don't need an sl_ops
implementation for 'write_timebase_ctrl' for to populate this register
for PSL9.

Hence this patch removes function write_timebase_ctrl_psl9() and its
references from the code.

Signed-off-by: Vaibhav Jain <[email protected]>
Acked-by: Andrew Donnellan <[email protected]>
Acked-by: Frederic Barrat <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>