Revert "Add extra EINVAL information about wrong block size to read(2)/write(2)"

This reverts commit 1c2be25f6080ee63baeae55e45761e1310d1b756.

kib@ pointed out that it is perfectly fine to write at arbitrary regular
file offsets. For example, in a 4K block size character device, geom
doesn't support writing / reading 515 byte blocks. The description is
perhaps not applicable to all EINVALs returned.

lib/libc/sys/read.2

@@ -28,7 +28,7 @@
 .\"     @(#)read.2	8.4 (Berkeley) 2/26/94
 .\" $FreeBSD$
 .\"
-.Dd October 7, 2022
+.Dd June 4, 2020
 .Dt READ 2
 .Os
 .Sh NAME
@@ -250,8 +250,6 @@ The sum of the
 values in the
 .Fa iov
 array overflowed a 32-bit integer.
-.It Bq Er EINVAL
-The current file offset is not a multiple of the block size.
 .It Bq Er EFAULT
 Part of the
 .Fa iov

lib/libc/sys/write.2

@@ -28,7 +28,7 @@
 .\"     @(#)write.2	8.5 (Berkeley) 4/2/94
 .\" $FreeBSD$
 .\"
-.Dd October 7, 2022
+.Dd February 11, 2021
 .Dt WRITE 2
 .Os
 .Sh NAME
@@ -205,8 +205,6 @@ is greater than
 if the sysctl
 .Va debug.iosize_max_clamp
 is non-zero).
-.It Bq Er EINVAL
-The current file offset is not a multiple of the block size.
 .It Bq Er EINTEGRITY
 The backing store for
 .Fa fd