use generic bits/fcntl.h for x86_64 and riscv64

these were only using a custom version because they needed the
"non-64" variants of the file locking command macros.

arch/riscv64/bits/fcntl.h

@@ -1,38 +0,0 @@
-#define O_CREAT        0100
-#define O_EXCL         0200
-#define O_NOCTTY       0400
-#define O_TRUNC       01000
-#define O_APPEND      02000
-#define O_NONBLOCK    04000
-#define O_DSYNC      010000
-#define O_SYNC     04010000
-#define O_RSYNC    04010000
-#define O_DIRECTORY 0200000
-#define O_NOFOLLOW  0400000
-#define O_CLOEXEC  02000000
-
-#define O_ASYNC      020000
-#define O_DIRECT     040000
-#define O_LARGEFILE 0100000
-#define O_NOATIME  01000000
-#define O_PATH    010000000
-#define O_TMPFILE 020200000
-#define O_NDELAY O_NONBLOCK
-
-#define F_DUPFD  0
-#define F_GETFD  1
-#define F_SETFD  2
-#define F_GETFL  3
-#define F_SETFL  4
-#define F_GETLK  5
-#define F_SETLK  6
-#define F_SETLKW 7
-#define F_SETOWN 8
-#define F_GETOWN 9
-#define F_SETSIG 10
-#define F_GETSIG 11
-
-#define F_SETOWN_EX 15
-#define F_GETOWN_EX 16
-
-#define F_GETOWNER_UIDS 17

arch/x86_64/bits/fcntl.h

@@ -1,40 +0,0 @@
-#define O_CREAT        0100
-#define O_EXCL         0200
-#define O_NOCTTY       0400
-#define O_TRUNC       01000
-#define O_APPEND      02000
-#define O_NONBLOCK    04000
-#define O_DSYNC      010000
-#define O_SYNC     04010000
-#define O_RSYNC    04010000
-#define O_DIRECTORY 0200000
-#define O_NOFOLLOW  0400000
-#define O_CLOEXEC  02000000
-
-#define O_ASYNC      020000
-#define O_DIRECT     040000
-#define O_LARGEFILE 0100000
-#define O_NOATIME  01000000
-#define O_PATH    010000000
-#define O_TMPFILE 020200000
-#define O_NDELAY O_NONBLOCK
-
-#define F_DUPFD  0
-#define F_GETFD  1
-#define F_SETFD  2
-#define F_GETFL  3
-#define F_SETFL  4
-
-#define F_SETOWN 8
-#define F_GETOWN 9
-#define F_SETSIG 10
-#define F_GETSIG 11
-
-#define F_GETLK 5
-#define F_SETLK 6
-#define F_SETLKW 7
-
-#define F_SETOWN_EX 15
-#define F_GETOWN_EX 16
-
-#define F_GETOWNER_UIDS 17