configs: synquacer: Make U-Boot binary position independent

Make the U-Boot binary for SynQuacer position independent so
that the previous bootloader (SCP firmware or BL2) can load
the U-Boot anywhere.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu@linaro.org>

configs/synquacer_developerbox_defconfig

 CONFIG_ARM=y
+CONFIG_POSITION_INDEPENDENT=y
 CONFIG_ARCH_SYNQUACER=y
-CONFIG_SYS_TEXT_BASE=0x08200000
+CONFIG_SYS_TEXT_BASE=0x00000000
 CONFIG_ENV_SIZE=0x30000
 CONFIG_ENV_OFFSET=0x300000
 CONFIG_ENV_SECT_SIZE=0x10000