mpc85xx: xpedite550x: remove CONFIG_FDT_FIXUP_PCI_IRQ

This macro is defined, but not referenced by anyone.

I did not touch config_whitelist.txt - the CONFIG will be dropped
by the next re-sync.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

include/configs/xpedite550x.h

@@ -204,7 +204,6 @@ extern unsigned long get_board_ddr_clk(unsigned long dummy);
 #define CONFIG_LOADS_ECHO		1	/* echo on for serial download */
 #define CONFIG_SYS_LOADS_BAUD_CHANGE	1	/* allow baudrate change */
 
-#define CONFIG_FDT_FIXUP_PCI_IRQ	1
 
 /*
  * I2C