x86/pci/ce4100: Remove unused 'struct sim_reg_op'

'struct sim_reg_op' wasn't ever used since it was introduced
14 years ago via:

  91d8037f ("ce4100: Add PCI register emulation for CE4100")

Remove it.

[ mingo: Improved the changelog. ]
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20240507232348.46677-1-linux@treblig.org

arch/x86/pci/ce4100.c

@@ -35,12 +35,6 @@ struct sim_dev_reg {
 	struct sim_reg sim_reg;
 };
 
-struct sim_reg_op {
-	void (*init)(struct sim_dev_reg *reg);
-	void (*read)(struct sim_dev_reg *reg, u32 value);
-	void (*write)(struct sim_dev_reg *reg, u32 value);
-};
-
 #define MB (1024 * 1024)
 #define KB (1024)
 #define SIZE_TO_MASK(size) (~(size - 1))