gas: change meaning of ; in the BPF assembler

gas: change meaning of ; in the BPF assembler

The BPF assembler in clang uses semi-colon (;) to separate statements,
not to be begin line comments.  This patch adapts the GNU assembler
accordingly.

Testsuite and documentation updated accordingly.

2023-11-28  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* config/tc-bpf.c: Semicolon does not start a comment, but
	separates multiple commands on a single line.
	* testsuite/gas/bpf/alu-pseudoc.s: Adapt test accordingly.
	* testsuite/gas/bpf/spacing-pseudoc.s: Likewise.
	* testsuite/gas/bpf/offset16-overflow.s: Likewise.
	* testsuite/gas/bpf/jump-relax-jump.s: Likewise.
	* testsuite/gas/bpf/jump-relax-ja.s: Likewise.
	* testsuite/gas/bpf/imm32-overflow.s: Likewise.
	* testsuite/gas/bpf/disp32-overflow.s: Likewise.
	* testsuite/gas/bpf/disp16-overflow-relax.s: Likewise.
	* testsuite/gas/bpf/disp16-overflow.s: Likewise.
	* doc/c-bpf.texi (BPF Special Characters): Update.