Porting BLEv1.2 Projects to BLEv1.3 Number of virtual registers

Hi TIers：

Porting1.2 to1.32，set Number of virtual registers to 16。

virtual registers是什么，为什么要设置为16呢？

请参考这个链接：http://e2e.ti.com/support/low_power_rf/f/538/t/237483.aspx

<EW8051_CompilerReference.pdf>

The compiler uses a set of virtual registers—located in data memory—to be used like any other registers. A minimum of 8 virtual registers are required by the compiler, but as many as 32 can be used. A larger set of virtual registers makes it possible for the compiler to allocate more variables into registers. However, a larger set of virtual registers also requires a larger data memory area. In the Large data model you should probably use a larger number of virtual registers, for example 32, to help the compiler generate better code.