repair hard fault return bug

before modify,when exception hook returns true,programs can't return to normal execution flow

libcpu/arm/cortex-m7/context_rvds.S

@@ -10,6 +10,7 @@
 ; * 2013-06-18     aozima       add restore MSP feature.
 ; * 2013-06-23     aozima       support lazy stack optimized.
 ; * 2018-07-24     aozima       enhancement hard fault exception handler.
+; * 2021-02-15     lizhirui     repair hard fault return bug
 ; */
 
 ;/**
@@ -235,11 +236,6 @@ MemManage_Handler
     ENDIF
     STMFD   r0!, {lr}               ; push exec_return register
 
-    TST     lr, #0x04               ; if(!EXC_RETURN[2])
-    ITE     EQ
-    MSREQ   msp, r0                 ; [2]=0 ==> Z=1, update stack pointer to MSP.
-    MSRNE   psp, r0                 ; [2]=1 ==> Z=0, update stack pointer to PSP.
-
     PUSH    {lr}
     BL      rt_hw_hard_fault_exception
     POP     {lr}