linux-user: Add support for setsockopt() option SOL_ALG

linux-user: Add support for setsockopt() option SOL_ALG

Add support for options SOL_ALG of the syscall setsockopt(). This
option is used in relation to Linux kernel Crypto API, and allows
a user to set additional information for the cipher operation via
syscall setsockopt(). The field "optname" must be one of the
following:

  - ALG_SET_KEY – seting the key
  - ALG_SET_AEAD_AUTHSIZE – set the authentication tag size

SOL_ALG is relatively newer setsockopt() option. Therefore, the
code that handles SOL_ALG is enclosed in "ifdef" so that the build
does not fail for older kernels that do not contain support for
SOL_ALG. "ifdef" also contains check if ALG_SET_KEY and
ALG_SET_AEAD_AUTHSIZE are defined.

Signed-off-by: Yunqiang Su <ysu@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <1560953834-29584-3-git-send-email-aleksandar.markovic@rt-rk.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>