Fix compilation issues with clang on POWER

As gcc defaults to -malign-power, removing that option. Also
adding -fno-integrated-as to use GNU assembler for powerpc
assembly optimization files. Fixed other compilation errors
reported in dgemv_t.c file.

kernel/power/dgemv_t.c

@@ -359,7 +359,7 @@ static void dgemv_kernel_4x8(BLASLONG n, BLASLONG lda, double *ap, double *x, do
             "stxvd2x 39, %[off], %[y]  \n\t"
             "stxvd2x 40, %[off2], %[y]  \n\t"     
                  
-            : [memy] "+m" (*(const double (*)[8])y),
+            : [memy] "+m" (*(double (*)[8])y),
             [n] "+&r" (n),
             [a0] "=b" (a0),
             [a1] "=&b" (a1),
@@ -373,7 +373,7 @@ static void dgemv_kernel_4x8(BLASLONG n, BLASLONG lda, double *ap, double *x, do
             [off2]"=&b" (off2),
             [temp] "=&b" (tempR)
             : [memx] "m" (*(const double (*)[n])x),
-            [mem_ap] "m" (*(const double (*)[]) ap),
+            [mem_ap] "m" (*(const double (*)[n*8]) ap),
             [alpha] "d" (alpha),
             "[a0]" (ap),
             [x] "b" (x),