Replace P2ALIGN with P2ALIGN_TYPED and delete P2ALIGN.

In P2ALIGN, the result would be incorrect when align is unsigned
integer and x is larger than max value of the type of align.
In that case, -(align) would be a positive integer, which means
high bits would be zero and finally stay zero after '&' when
align is converted to a larger integer type.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Youzhong Yang <yyang@mathworks.com>
Signed-off-by: Qiuhao Chen <chenqiuhao1997@gmail.com>
Closes #15940