src/cpu/power9: move part of scom.h to scom.c

Reset function, constants and include are not used outside of scom.c and
not going to be.

Change-Id: Iff4e98ae52c7099954f0c20fcb639eb87af15534
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67055
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michał Kopeć <michal.kopec@3mdeb.com>

src/include/cpu/power/scom.h

@@ -30,13 +30,10 @@
 // Higher bits specify indirect address
 
 #define XSCOM_ADDR_IND_FLAG		PPC_BIT(0)
-#define XSCOM_ADDR_IND_ADDR		PPC_BITMASK(11, 31)
-#define XSCOM_ADDR_IND_DATA		PPC_BITMASK(48, 63)
 
 #ifndef __ASSEMBLER__
 #include <types.h>
 #include <arch/io.h>
-#include <cpu/power/spr.h>
 
 // TODO: these are probably specific to POWER9
 typedef enum {
@@ -88,8 +85,6 @@ typedef enum {
 	EC23_CHIPLET_ID = 0x37      ///< Core23 chiplet (Quad5, EX11, C1)
 } chiplet_id_t;
 
-void reset_scom_engine(void);
-
 uint64_t read_scom_direct(uint64_t reg_address);
 void write_scom_direct(uint64_t reg_address, uint64_t data);