Refactor Readme after comment from Tech Writer

Rephrase usage guideline on `objects.h` and explain usage of every label
in `targets.json`

Author: Ron Eldor

features/mbedtls/targets/TARGET_CRYPTOCELL310/Readme.md

@@ -6,15 +6,15 @@ The CC 310 driver consists of three libraries:
 
 * A common core library(`libcc_core.a`).
 * A platform-specific TRNG library, containing TRNG-related information, for sampling sufficient entropy on the specific platform(`libcc_trng.a`).
-* A platform-specific library containig extra information, such as the CC register's base addresses on the specific board. (`libcc_ext.a`)
+* A platform-specific library containing extra information, such as the CC register's base addresses on the specific board. (`libcc_ext.a`)
 
 To port your CC 310 driver to Mbed OS on your specific target, do the following:
 
 1. In `targets.json` add the following  to your target:
- 	* `MBEDTLS_CONFIG_HW_SUPPORT` to `macros_add` key.
- 	* `CRYPTOCELL` to `device_has_add` key.
- 	* `CRYPTOCELL310` to `extra_labels_add` key.
-1. In `objects.h`, include `objects_cryptocell.h`. (You can condition it with `#if DEVICE_CRYPTOCELL` in case you have another `trng` engine for a differnt board, and `objects.h` is common file for your boards, in this case your common `trng_api.c` file should be compiled only if `#if !defined(DEVICE_CRYPTOCELL)`).
+ 	* `MBEDTLS_CONFIG_HW_SUPPORT` to `macros_add` key. This is used to suggest there is HW accelerated cryptography engine that will replace the default Mbed TLS implementation.
+ 	* `CRYPTOCELL` to `device_has_add` key. This should be used in your common code, that you need to remove from compilation in case CC exists in your board. Use `#if !defined(DEVICE_CRYPTOCELL)` or  `#if DEVICE_CRYPTOCELL`.
+ 	* `CRYPTOCELL310` to `extra_labels_add` key. This is used for the build system to look for the CC 310 code and binaries.
+1. In `objects.h`, include `objects_cryptocell.h`. You can use the `DEBICE_CRYPTOCELL` pre-compilation check as defined above.
 1. In `features/mbedtls/targets/TARGET_CRYPTOCELL310/TARGET_<target name>`, add your platform-specific libraries for all toolchains in `TOOLCHAIN_ARM`, `TOOLCHAIN_GCC_ARM` and `TOOLCHAIN_IAR` respectively.
 1. Add your CC setup code:
 	* Implement `cc_platform_setup()` and `cc_platform_terminate()` to enable CC on your platform, in case you have such limitations. You can implement these functions as empty functions.