bhyve: return ENOMEM instead of EFAULT and call free() after being used

1. In basl_load() function, when allocation fails,

it returns an EFAULT instead of ENOMEM. An EFAULT
can mislead in some scenarios, whereas an ENOMEM
for an allocation function makes much more sense.

2. Call free() on addr, as it's not being used

anymore after the basl_table_append_bytes()
function.

Signed-off-by: rilysh <nightquick@proton.me>

MFC after: 1 week
Pull Request: https://github.com/freebsd/freebsd-src/pull/1016

(cherry picked from commit e2e956828caf2f1db308d54b264c277c0abc25df)