tcs34725: Remove asserts form shell commands
tcs34725: Remove asserts form shell commands

Shell command dump will now print error information
instead of asserting.
Code reading sensor was called inside assert which could
be removed leaving only prints without actual register readings.
This also reduces code size of dump command.
Printed register names are now same as ones found in header file.

mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core