sb,soc/amd: Remove unused southbridge_io_trap_handler()

At the moment IO trap is not implemented for AMD platforms.

Change-Id: Ib62ac4e4e418a8bab80c30dfb5183ecd8beb998d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70360
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/soc/amd/cezanne/smihandler.c

@@ -105,11 +105,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in fch.c is unrelated to this list.

src/soc/amd/glinda/smihandler.c

@@ -105,11 +105,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in fch.c is unrelated to this list.

src/soc/amd/mendocino/smihandler.c

@@ -105,11 +105,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in fch.c is unrelated to this list.

src/soc/amd/morgana/smihandler.c

@@ -105,11 +105,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in fch.c is unrelated to this list.

src/soc/amd/picasso/smihandler.c

@@ -107,11 +107,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in fch.c is unrelated to this list.

src/soc/amd/stoneyridge/smihandler.c

@@ -129,11 +129,6 @@ static void fch_slp_typ_handler(void)
 	}
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 /*
  * Table of functions supported in the SMI handler.  Note that SMI source setup
  * in southbridge.c is unrelated to this list.

src/southbridge/amd/pi/hudson/smihandler.c

@@ -43,11 +43,6 @@ static void hudson_apmc_smi_handler(void)
 	mainboard_smi_apmc(cmd);
 }
 
-int southbridge_io_trap_handler(int smif)
-{
-	return 0;
-}
-
 static void process_smi_sci(void)
 {
 	const uint32_t status = smi_read32(0x10);