tools/imximage: Fix fruity lack of 0x prefix in DCD Blocks

tools/imximage: Fix fruity lack of 0x prefix in DCD Blocks

commit 8519c9c98ad6 ("tools/imximage: use 0x prefix in HAB Blocks line")
adds an 0x prefix to each HAB Block number to make it easier for host tools
to process the HAB Block output, however it neglects to apply the same
prefix to the DCD Blocks directive. You need the DCD Blocks directive if
you are making a u-boot recovery image which the BootROM will accept via
the USB upload utility.

This disparity results in a fruity output like this with HAB Blocks
prefixed but DCD Blocks not prefixed - which is pretty inconsistent.

This patch fixes the difference assuming the original commit was a
legitimate change.

Old:
Image Type:   Freescale IMX Boot Image
Image Ver:    2 (i.MX53/6/7 compatible)
Mode:         DCD
Data Size:    430080 Bytes = 420.00 KiB = 0.41 MiB
Load Address: 877ff420
Entry Point:  87800000
HAB Blocks:   0x877ff400 0x00000000 0x00066c00
DCD Blocks:   00910000 0000002c 000001d4

New:
Image Type:   Freescale IMX Boot Image
Image Ver:    2 (i.MX53/6/7 compatible)
Mode:         DCD
Data Size:    430080 Bytes = 420.00 KiB = 0.41 MiB
Load Address: 877ff420
Entry Point:  87800000
HAB Blocks:   0x877ff400 0x00000000 0x00066c00
DCD Blocks:   0x00910000 0x0000002c 0x000001d4

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Breno Lima <breno.lima@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>