MSDK: MAX32662: remove .shared and mailbox sections

The .shared and .mailbox sections are for the dual-core parts and
don’t exist for the MAX32662

Signed-off-by: Sadik Ozer <[email protected]>

Author: ozersa

MAX/Libraries/CMSIS/Device/Maxim/MAX32662/Source/system_max32662.c

@@ -32,8 +32,7 @@
 
 extern void (*const __isr_vector[])(void);
 
-uint32_t SystemCoreClock __attribute__((section(".shared")));
-volatile uint32_t mailbox __attribute__((section(".mailbox")));
+uint32_t SystemCoreClock = HIRC_FREQ;
 
 /*
 The libc implementation from GCC 11+ depends on _getpid and _kill in some places.