device: Constify struct device * parameter to acpi_fill_ssdt()

.acpi_fill_ssdt() does not need to modify the device structure. This
change makes the struct device * parameter to acpi_fill_ssdt() as
const.

Change-Id: I110f4c67c3b6671c9ac0a82e02609902a8ee5d5c
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40710
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/intel/speedstep/acpi.c

@@ -81,7 +81,7 @@ static void gen_pstate_entries(const sst_table_t *const pstates,
 /**
  * @brief Generate ACPI entries for Speedstep for each cpu
  */
-void generate_cpu_entries(struct device *device)
+void generate_cpu_entries(const struct device *device)
 {
 	int coreID, cpuID, pcontrol_blk = PMB0_BASE, plen = 6;
 	int totalcores = determine_total_number_of_cores();