arm: qemu: fix failure in flash initialization if booting from TF-A

arm: qemu: fix failure in flash initialization if booting from TF-A

If U-Boot is loaded and started from TF-A (you need to change
SYS_TEXT_BASE to 0x60000000), it will hang up at flash initialization.

If secure mode is off (default, or -machine virt,secure=off) at qemu,
it will provide dtb with two flash memory banks:
	flash@0 {
		bank-width = <0x4>;
		reg = <0x0 0x0 0x0 0x4000000 0x0 0x4000000 0x0 0x4000000>;
		compatible = "cfi-flash";
	};
If secure mode is on, on the other hand, qemu provides dtb with 1 bank:
	flash@0 {
		bank-width = <0x4>;
		reg = <0x0 0x4000000 0x0 0x4000000>;
		compatible = "cfi-flash";
	};

As a result, flash_init()/flash_get_size() will eventually fail.
With this patch applied, relevant CONFIG values are modified.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>