Fix comparison of integer expressions of different signedness

[rleh]

Fix comparison of integer expressions of different signedness

Description

When compiling with -Werror=sign-compare flag and with the default config values (FreeRTOSIPConfigDefaults.h) the integer comparison of different signedness in FreeRTOS_TCP_WIN.c:1874 leads to an error, because winSRTT_CAP_mS evaluates to 50U.
This PR removes the unsigned literal.

Test Steps

Compile with -Werror=sign-compare flag and without a user-defined value for ipconfigTCP_SRTT_MINIMUM_VALUE_MS.

Related Issue

FreeRTOS_TCP_WIN.c: In function 'prvTCPWindowTxCheckAck_CalcSRTT':
FreeRTOS_TCP_WIN.c:1874:33: error: comparison of integer expressions of different signedness: 'int32_t' {aka 'long int'} and 'unsigned int' [-Werror=sign-compare]
 1874 |             if( pxWindow->lSRTT < winSRTT_CAP_mS )
      |                                 ^

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice. ✅

[htibosch]

Thank you Raphael for this PR.
I approve it.
It may take a while before it will be approved and merged.

[htibosch]

Yes correct, as the value will be compared with an int32_t

[AniruddhaKanhere]

@rleh thanks for this PR.

For short term I think this is okay, but since milliseconds cannot be negative, I think that the macro should be reverted back to the original value of 50U and the variable should be modified to be uint32_t if it only ever holds milliseconds.