MFamd64 r322720, r322723:
Simplify i386 trap().

• Use more relevant name 'signo' instead of 'i' for the local variable which contains a signal number to send for the current exception.
• Eliminate two labels 'userout' and 'out' which point to the very end of the trap() function. Instead use return directly.
• Re-indent the prot_fault_translation block by reducing if() nesting.
• Some more monor style changes.

Reviewed by: bde
Sponsored by: The FreeBSD Foundation
MFC after: 1 week