MIPS: drop asm/const.h

Commit 86f21c96f467368 (mips: Use common _AC macro now.) removed the _AC
definition from const.h. All other macros defined in const.h are not
used anywhere, and there is now no user of this header. Remove this
header.

Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>

arch/mips/include/asm/const.h

@@ -1,27 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * const.h: Macros for dealing with constants.
- */
-
-#ifndef _LINUX_CONST_H
-#define _LINUX_CONST_H
-
-/* Some constant macros are used in both assembler and
- * C code.  Therefore we cannot annotate them always with
- * 'UL' and other type specifiers unilaterally.  We
- * use the following macros to deal with this.
- *
- * Similarly, _AT() will cast an expression with a type in C, but
- * leave it unchanged in asm.
- */
-
-#ifdef __ASSEMBLY__
-#define _AT(T,X)	X
-#else
-#define _AT(T,X)	((T)(X))
-#endif
-
-#define _BITUL(x)	(_AC(1,UL) << (x))
-#define _BITULL(x)	(_AC(1,ULL) << (x))
-
-#endif /* !(_LINUX_CONST_H) */