Drop CONFIG_HAS_DATAFLASH

Last user of this option went away in commit:

fdc7718999 ("board: usb_a9263: Update to support DT and DM")

Signed-off-by: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
diff --git a/arch/arm/mach-at91/arm926ejs/at91sam9261_devices.c b/arch/arm/mach-at91/arm926ejs/at91sam9261_devices.c
index 4bd4e75..58050a2 100644
--- a/arch/arm/mach-at91/arm926ejs/at91sam9261_devices.c
+++ b/arch/arm/mach-at91/arm926ejs/at91sam9261_devices.c
@@ -55,7 +55,7 @@
 	at91_periph_clk_enable(ATMEL_ID_SYS);
 }
 
-#if defined(CONFIG_HAS_DATAFLASH) || defined(CONFIG_ATMEL_SPI)
+#ifdef CONFIG_ATMEL_SPI
 void at91_spi0_hw_init(unsigned long cs_mask)
 {
 	at91_set_a_periph(AT91_PIO_PORTA, 0, PUP);	/* SPI0_MISO */