nxp: fix vector redefinition from CMSIS

Since 5.7 CMSIS update to Mbed OS, __VECTOR_TABLE is defined in cmsis_gcc header
file. Many MCU in NXP uses this symbol as linker definition, therefore we should
check if already defined and undefined it.

Fixes #13062

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/fsl_common.c

@@ -29,6 +29,12 @@
 */
 
 #include "fsl_common.h"
+
+/* At least CMSIS 5.7 introduced vector table and define this GCC linker symbol to
+ __Vectors - not valid for many NXP MCU. To fix this, we undefine it if already defined
+ as it comes from a linker */
+#undef __VECTOR_TABLE
+
 void InstallIRQHandler(IRQn_Type irq, uint32_t irqHandler)
 {
 /* Addresses for VECTOR_TABLE and VECTOR_RAM come from the linker file */