sunxi: Drop qt840a_defconfig

The qt840a is one of the many tv-boxes using the "i12" A20 pcb, but it
populates only one of the 2 places for a 16 bit dram ic, thus reducing
the buswidth to 16 bits, and the amount of ram to 512M, which is why we
had a separate config for it.

This commit switches the generic i12-tvbox_defconfig over to DRAM
autoconfiguration, so that it will work with the qt840a too, and drops the
qt840a specific config, like we've done with other memory-amount specific
configs before.

Tested on a generic i12-tvbox with 32 bit bus-width / 1G RAM, and on a
qt840a with 16 bit bus-width / 512M RAM.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/configs/i12-tvbox_defconfig b/configs/i12-tvbox_defconfig
index 5f5037e..65791b7 100644
--- a/configs/i12-tvbox_defconfig
+++ b/configs/i12-tvbox_defconfig
@@ -5,3 +5,6 @@
 +S:CONFIG_ARCH_SUNXI=y
 +S:CONFIG_MACH_SUN7I=y
 +S:CONFIG_TARGET_I12_TVBOX=y
++S:CONFIG_DRAM_CLK=384
++S:CONFIG_DRAM_ZQ=127
++S:CONFIG_DRAM_EMR1=4