fix(area): Use unsigned integer literal for bit shifing.

[jakobvukalovic]

Fixes hicpp-signed-bitwise error.

Description of the feature or fix

Use unsigned integer literals for _LV_COORD_TYPE_SHIFT to silence clang-tidy error about using signed integer to perform bitshift operations (hicpp-signed-bitwise).

Checkpoints

• Follow the styling guide
• Run code-format.py from the scripts folder. astyle needs to be installed.
• Update the documentation

[kisvegabor]

Thanks!