optimize zgemm lsx kernel for 2k3000 cpu

[ErnstPeng]

On the 2k3000 CPU, the performance of zgemm lsx is not good. The kernel was optimized and the PQR parameters were set according to the hardware characteristics.
performance of ./zgemm.goto 1000 2000 100, LOOPS=20 THREADS=8,
before:

M=1000,N=1000,	K=1000:	40705.41 MFlops	1.965341 sec
M=1100,N=1100,	K=1100:	42272.97 MFlops	2.518867 sec
M=1200,N=1200,	K=1200:	41692.56 MFlops	3.3157	 sec
M=1300,N=1300,	K=1300:	41171.31 MFlops	4.268993 sec
M=1400,N=1400,	K=1400:	42131.12 MFlops	5.210401 sec
M=1500,N=1500,	K=1500:	41990.57 MFlops	6.430015 sec
M=1600,N=1600,	K=1600:	42440.13 MFlops	7.720994 sec
M=1700,N=1700,	K=1700:	42314.03 MFlops	9.288645 sec
M=1800,N=1800,	K=1800:	42347.5	 MFlops	11.017415 sec
M=1900,N=1900,	K=1900:	42294.43 MFlops	12.973811 sec
M=2000,N=2000,	K=2000:	42755.69 MFlops	14.968767 sec

after:

M=1000,N=1000,	K=1000:	48969.39 MFlops	3.267347 sec
M=1100,N=1100,	K=1100:	49745.22 MFlops	4.281014 sec
M=1200,N=1200,	K=1200:	50175.55 MFlops	5.510254 sec
M=1300,N=1300,	K=1300:	50176.97 MFlops	7.005605 sec
M=1400,N=1400,	K=1400:	50822.99 MFlops	8.63861	 sec
M=1500,N=1500,	K=1500:	50509.5	 MFlops	10.691058 sec
M=1600,N=1600,	K=1600:	51319.72 MFlops	12.77014 sec
M=1700,N=1700,	K=1700:	51523.32 MFlops	15.256781 sec
M=1800,N=1800,	K=1800:	51183.36 MFlops	18.230923 sec
M=1900,N=1900,	K=1900:	51136.7	 MFlops	21.460909 sec
M=2000,N=2000,	K=2000:	51041.54 MFlops	25.077615 sec

[ErnstPeng]

@XiWeiGu