MIPS: Simplify __bswapdi2() and __bswapsi2()

Use macro definitions ___constant_swab64 and ___constant_swab32
to simplify __bswapdi2() and __bswapsi2().
Signed-off-by: NTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/lib/bswapdi.c

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/export.h>
 #include <linux/compiler.h>
+#include <uapi/linux/swab.h>
 
 /* To silence -Wmissing-prototypes. */
 unsigned long long __bswapdi2(unsigned long long u);
 
 unsigned long long notrace __bswapdi2(unsigned long long u)
 {
-	return (((u) & 0xff00000000000000ull) >> 56) |
-	       (((u) & 0x00ff000000000000ull) >> 40) |
-	       (((u) & 0x0000ff0000000000ull) >> 24) |
-	       (((u) & 0x000000ff00000000ull) >>  8) |
-	       (((u) & 0x00000000ff000000ull) <<  8) |
-	       (((u) & 0x0000000000ff0000ull) << 24) |
-	       (((u) & 0x000000000000ff00ull) << 40) |
-	       (((u) & 0x00000000000000ffull) << 56);
+	return ___constant_swab64(u);
 }
 EXPORT_SYMBOL(__bswapdi2);

arch/mips/lib/bswapsi.c

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/export.h>
 #include <linux/compiler.h>
+#include <uapi/linux/swab.h>
 
 /* To silence -Wmissing-prototypes. */
 unsigned int __bswapsi2(unsigned int u);
 
 unsigned int notrace __bswapsi2(unsigned int u)
 {
-	return (((u) & 0xff000000) >> 24) |
-	       (((u) & 0x00ff0000) >>  8) |
-	       (((u) & 0x0000ff00) <<  8) |
-	       (((u) & 0x000000ff) << 24);
+	return ___constant_swab32(u);
 }
 EXPORT_SYMBOL(__bswapsi2);