math: Fix sqrt losing precision for a very small values of x

[agkaminski]

DONE: RTOS-548

Description

Fixes phoenix-rtos/phoenix-rtos-project#766

As it turns out, algorithm works just fine, whole problem was in this one line.
It was done to make single precision division instead of double precision to increase performance. But now it's of lower priority, as hardware accelerated implementation of sqrt is used on most targets. On targets with soft fpu it matters as little, as all float operations are low performance.

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: (PC).

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[badochov]

LGTM