Remove keep keyword for .heap section

Author: linlingao

targets/TARGET_Cypress/TARGET_PSOC6/TARGET_CY8CPROTO_064_SB/device/TOOLCHAIN_GCC_ARM/cyb06xx7_cm4_dual.ld

@@ -357,7 +357,7 @@ SECTIONS
         __HeapBase = .;
         __end__ = .;
         end = __end__;
-        KEEP(*(.heap*))
+        *(.heap*)
         . = ORIGIN(ram) + LENGTH(ram) - STACK_SIZE;
         __HeapLimit = .;
     } > ram