flash: Flash bootloader first before determining emmc size

This solves the case where we have an old bootloader and don't have the
appropriate fastboot vars available to determine emmc size.

Change-Id: I93558d821f274599c1fb0a17bd16ff2cfc2a82f1
diff --git a/flash.sh b/flash.sh
index 623be3b..2f3d25f 100755
--- a/flash.sh
+++ b/flash.sh
@@ -24,6 +24,10 @@
     esac
 }
 
+# Flash bootloader
+fastboot flash bootloader0 ${PRODUCT_OUT}/u-boot.imx
+fastboot reboot-bootloader
+
 # Figure out which partition map we need based upon fastboot vars
 MMC_SIZE=$(fastboot getvar mmc_size 2>&1 | awk '/mmc_size:/ { print $2 }')
 PART_IMAGE=$(partition_table_image ${MMC_SIZE})
@@ -33,10 +37,6 @@
     exit 1
 fi
 
-# Flash bootloader
-fastboot flash bootloader0 ${PRODUCT_OUT}/u-boot.imx
-fastboot reboot-bootloader
-
 # Flash partition table
 fastboot flash gpt ${PRODUCT_OUT}/${PART_IMAGE}
 fastboot reboot-bootloader