Align packed panel strides with system alignment.

Details:
- Pass panel strides through bli_align_dim_to_sys() to ensure that each
  subsequent packed panel of A and B begins at an aligned address. (The
  first panel is presumably aligned to system alignment because it is
  aligned to a page boundary, which is typically much larger.)
- Rearranged code in packm_init_pack() to prevent additional conditional
  blocks as a result of the aforementioned change.
- Adjusted contiguous memory allocator so that the system memory alignment
  is used to allocate enough space for each block no matter what kind of
  register blocking is used (even if register blocksize is unit and every
  row/column needs maximal padding).
- Adjusted default blocksizes in reference configuration so that MC*KC
  and KC*NC result in identical footprints for all datatypes.

config/reference/bli_kernel.h

@@ -61,21 +61,21 @@
 // and thus it would be constraint (2b) that would be needed instead of (1b).
 //
 
-#define BLIS_DEFAULT_MC_S              128
+#define BLIS_DEFAULT_MC_S              256
 #define BLIS_DEFAULT_KC_S              256
 #define BLIS_DEFAULT_NC_S              8192
 
 #define BLIS_DEFAULT_MC_D              128
 #define BLIS_DEFAULT_KC_D              256
-#define BLIS_DEFAULT_NC_D              8192
+#define BLIS_DEFAULT_NC_D              4096
 
 #define BLIS_DEFAULT_MC_C              128
 #define BLIS_DEFAULT_KC_C              256
-#define BLIS_DEFAULT_NC_C              8192
+#define BLIS_DEFAULT_NC_C              4096
 
-#define BLIS_DEFAULT_MC_Z              128
+#define BLIS_DEFAULT_MC_Z              64
 #define BLIS_DEFAULT_KC_Z              256
-#define BLIS_DEFAULT_NC_Z              8192
+#define BLIS_DEFAULT_NC_Z              2048
 
 // -- Default register blocksizes for inner kernel --