common: do not compile common fastboot code when building the SPL

This is not required as fastboot can't be started from SPL.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

common/Makefile

@@ -109,6 +109,7 @@ obj-$(CONFIG_IO_TRACE) += iotrace.o
 obj-y += memsize.o
 obj-y += stdio.o
 
+ifndef CONFIG_SPL_BUILD
 # This option is not just y/n - it can have a numeric value
 ifdef CONFIG_FASTBOOT_FLASH
 obj-y += image-sparse.o
@@ -119,6 +120,7 @@ ifdef CONFIG_FASTBOOT_FLASH_NAND_DEV
 obj-y += fb_nand.o
 endif
 endif
+endif
 
 ifdef CONFIG_CMD_EEPROM_LAYOUT
 obj-y += eeprom/eeprom_field.o eeprom/eeprom_layout.o