Use consistent/modern code formatting for pointers

The convention used by libjpeg:

    type * variable;

is not very common anymore, because it looks too much like
multiplication.  Some (particularly C++ programmers) prefer to tuck the
pointer symbol against the type:

    type* variable;

to emphasize that a pointer to a type is effectively a new type.
However, this can also be confusing, since defining multiple variables
on the same line would not work properly:

    type* variable1, variable2;  /* Only variable1 is actually a
                                    pointer. */

This commit reformats the entirety of the libjpeg-turbo code base so
that it uses the same code formatting convention for pointers that the
TurboJPEG API code uses:

    type *variable1, *variable2;

This seems to be the most common convention among C programmers, and
it is the convention used by other codec libraries, such as libpng and
libtiff.
diff --git a/simd/jidctred-sse2.asm b/simd/jidctred-sse2.asm
index 06dade8..e48c0c5 100644
--- a/simd/jidctred-sse2.asm
+++ b/simd/jidctred-sse2.asm
@@ -99,11 +99,11 @@
 ; producing a reduced-size 4x4 output block.
 ;
 ; GLOBAL(void)
-; jsimd_idct_4x4_sse2 (void * dct_table, JCOEFPTR coef_block,
+; jsimd_idct_4x4_sse2 (void *dct_table, JCOEFPTR coef_block,
 ;                      JSAMPARRAY output_buf, JDIMENSION output_col)
 ;
 
-%define dct_table(b)    (b)+8           ; void * dct_table
+%define dct_table(b)    (b)+8           ; void *dct_table
 %define coef_block(b)   (b)+12          ; JCOEFPTR coef_block
 %define output_buf(b)   (b)+16          ; JSAMPARRAY output_buf
 %define output_col(b)   (b)+20          ; JDIMENSION output_col
@@ -414,11 +414,11 @@
 ; producing a reduced-size 2x2 output block.
 ;
 ; GLOBAL(void)
-; jsimd_idct_2x2_sse2 (void * dct_table, JCOEFPTR coef_block,
+; jsimd_idct_2x2_sse2 (void *dct_table, JCOEFPTR coef_block,
 ;                      JSAMPARRAY output_buf, JDIMENSION output_col)
 ;
 
-%define dct_table(b)    (b)+8           ; void * dct_table
+%define dct_table(b)    (b)+8           ; void *dct_table
 %define coef_block(b)   (b)+12          ; JCOEFPTR coef_block
 %define output_buf(b)   (b)+16          ; JSAMPARRAY output_buf
 %define output_col(b)   (b)+20          ; JDIMENSION output_col