poplar: Fix format of documentation

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Change-Id: I6e243d17d7cb6247f91698bc195eb0f6efeb7d17
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

docs/plat/poplar.rst

@@ -11,6 +11,8 @@ of running any commercial set-top solution based on Linux or Android.
 It supports a premium user experience with up to H.265 HEVC decoding of 4K
 video at 60 frames per second.
 
+::
+
     SOC Hisilicon Hi3798CV200
     CPU Quad-core ARM Cortex-A53 64 bit
     DRAM DDR3/3L/4 SDRAM interface, maximum 32-bit data width 2 GB
@@ -28,6 +30,8 @@ At the start of the boot sequence, the bootROM executes the so called l-loader
 binary whose main role is to change the processor state to 64bit mode. This
 must  happen prior invoking the arm trusted  firmware:
 
+::
+
     l-loader --> arm_trusted_firmware --> u-boot
 
 How to build
@@ -54,10 +58,16 @@ Build Procedure
 -  Prepare the AARCH64 toolchain.
 
 -  Build u-boot using poplar_defconfig
+
+.. code:: bash
+
        make CROSS_COMPILE=aarch64-linux-gnu- poplar_defconfig
        make CROSS_COMPILE=aarch64-linux-gnu-
 
 -  Build atf providing the previously generated u-boot.bin as the BL33 image
+
+.. code:: bash
+
        make CROSS_COMPILE=aarch64-linux-gnu-  all fip SPD=none PLAT=poplar
        BL33=u-boot.bin
 
@@ -81,6 +91,8 @@ working firmware to eMMC.
 Boot trace
 ==========
 
+::
+
     Bootrom start
     Boot Media: eMMC
     Decrypt auxiliary code ...OK
@@ -162,4 +174,3 @@ USB device 0:
     ... is now current device
     Scanning usb 0:1...
     =>
-