Refactor excessive logic/side effects in return statement

[skliper]

Is your feature request related to a problem? Please describe.
Excessive logic in OS_FileSys_FindVirtMountPoint return statement. This isn't coding standard compliant and takes a while to sort out when first observed:

osal/src/os/shared/src/osapi-filesys.c

Lines 107 to 108 in ead5723

	return (mplen > 0 && mplen < sizeof(filesys->virtual_mountpt) &&
	strncmp(target, filesys->virtual_mountpt, mplen) == 0 && (target[mplen] == '/' || target[mplen] == 0));

Describe the solution you'd like
Refactor/comment to make more clear.

Describe alternatives you've considered
None

Additional context
None

Requester Info
Jacob Hageman - NASA/GSFC, OSAL code review