AGESA fam15: Fix entry to cimx/sb900

Move SB900 call to match comments and changes already made for
family14 et al.

Change-Id: I22aa0bbeeabf9cff929c49c23014005bc3d53ccb
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/6238
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/southbridge/amd/cimx/sb700/sb_cimx.h

@@ -34,7 +34,6 @@
 void sb_Poweron_Init(void);
 void sb_Before_Pci_Init(void);
 void sb_After_Pci_Init(void);
-void sb_Mid_Post_Init(void);
 void sb_Late_Post(void);
 
 void sb7xx_51xx_enable_wideio(u8 wio_index, u16 base);