Fix SH2A_FPU FPU context cleanup

[Old-Ding]

Summary

• Add portCLEAN_UP_TCB for the Renesas SH2A_FPU port so task deletion releases the FPU context buffer stored through pxTaskTag.
• Make xPortUsesFloatingPoint() idempotent when the task already has an FPU buffer, avoiding an immediate leak on repeated calls.
• Move the FPU buffer sizing macros to portmacro.h so port.c and the cleanup macro use the same constants.

Root cause

xPortUsesFloatingPoint() allocates the FPU context buffer and stores a pointer just past the allocation in pxTaskTag, because the save routine uses a pre-decrement. The port did not define portCLEAN_UP_TCB, so prvDeleteTCB() used the default no-op cleanup and the allocation became unreachable when the task was deleted.

Fixes #1443

Validation

• git diff --check
• rg confirmed the FPU buffer constants and portCLEAN_UP_TCB override are scoped to portable/Renesas/SH2A_FPU, with prvDeleteTCB() calling portCLEAN_UP_TCB( pxTCB ) before freeing the TCB/stack.
• Renesas SH toolchain/hardware build not run locally; no shc, ccsh, sh-elf-gcc, sh-none-elf-gcc, rx-elf-gcc, or ccrx command was found on this machine.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[rawalexe]

Buffer-reuse fix and portCLEAN_UP_TCB look correct. Confirmed the task tag stores the buffer end pointer (pulFlopBuffer + portFLOP_REGISTERS_TO_STORE), matching the pre-decrement convention used by the FPU save routine and the - portFLOP_REGISTERS_TO_STORE recovery in the cleanup macro. This correctly fixes the original leak/overwrite bug where a second call to xPortUsesFloatingPoint would silently drop the existing allocation. LGTM.