Use UBaseType_t for ullMachineTimerCompareRegisterBase (#1258)

Use architecture-dependent UBaseType_t instead of fixed type for
ullMachineTimerCompareRegisterBase. This type is defined to uint32_t or
uint64_t based on XLEN, resolving warnings on 32-bit platforms.

Reported by landretk@ on the PR FreeRTOS/FreeRTOS-Kernel#1176.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>

portable/GCC/RISC-V/port.c

@@ -90,7 +90,7 @@ void vPortSetupTimerInterrupt( void ) __attribute__( ( weak ) );
 uint64_t ullNextTime = 0ULL;
 const uint64_t * pullNextTime = &ullNextTime;
 const size_t uxTimerIncrementsForOneTick = ( size_t ) ( ( configCPU_CLOCK_HZ ) / ( configTICK_RATE_HZ ) ); /* Assumes increment won't go over 32-bits. */
-uint64_t const ullMachineTimerCompareRegisterBase = configMTIMECMP_BASE_ADDRESS;
+UBaseType_t const ullMachineTimerCompareRegisterBase = configMTIMECMP_BASE_ADDRESS;
 volatile uint64_t * pullMachineTimerCompareRegister = NULL;
 
 /* Holds the critical nesting value - deliberately non-zero at start up to

portable/IAR/RISC-V/port.c

@@ -98,7 +98,7 @@ void vPortSetupTimerInterrupt( void ) __attribute__( ( weak ) );
 uint64_t ullNextTime = 0ULL;
 const uint64_t * pullNextTime = &ullNextTime;
 const size_t uxTimerIncrementsForOneTick = ( size_t ) ( ( configCPU_CLOCK_HZ ) / ( configTICK_RATE_HZ ) ); /* Assumes increment won't go over 32-bits. */
-uint64_t const ullMachineTimerCompareRegisterBase = configMTIMECMP_BASE_ADDRESS;
+UBaseType_t const ullMachineTimerCompareRegisterBase = configMTIMECMP_BASE_ADDRESS;
 volatile uint64_t * pullMachineTimerCompareRegister = NULL;
 
 /* Holds the critical nesting value - deliberately non-zero at start up to