qcom_defconfig: bump CONFIG_NR_DRAM_BANKS

Some newer boards end up with a bunch of holes in the memory map due to
how Qualcomm's hypervisor and ABL work. The end result is 14+ memory
regions.

Bump CONFIG_NR_DRAM_BANKS to 24 so we can handle these and any future
expansion easily.

Yes, this is ridiculous, but there is no other way.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/configs/qcom_defconfig b/configs/qcom_defconfig
index edbb624..3488edd 100644
--- a/configs/qcom_defconfig
+++ b/configs/qcom_defconfig
@@ -3,6 +3,7 @@
 CONFIG_POSITION_INDEPENDENT=y
 CONFIG_SYS_INIT_SP_BSS_OFFSET=1572864
 CONFIG_ARCH_SNAPDRAGON=y
+CONFIG_NR_DRAM_BANKS=24
 CONFIG_DEFAULT_DEVICE_TREE="qcom/sdm845-db845c"
 CONFIG_SYS_LOAD_ADDR=0xA0000000
 CONFIG_BUTTON_CMD=y