Revert "package/libssh2: fix static linking scenarios involving mbedtls"

Revert "package/libssh2: fix static linking scenarios involving mbedtls"

This reverts commit 48218732a3a7b983825ff3a8cf0767f847ac8d04 because
LTLIBMBEDCRYPTO will return "-lmbedcrypto
-R/accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/lib"

On some compilers, -R option won't be recognized and this will prevent
the detection of libz:

configure:17809: /accts/mlweber1/scripts/instance-3/output/host/bin/i586-linux-gcc -o conftest -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os   -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I/accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/include  conftest.c /accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/lib/libz.so -Wl,-rpath -Wl,/accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/lib  -L/accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/lib -lmbedcrypto -R/accts/mlweber1/scripts/instance-3/output/host/i586-buildroot-linux-musl/sysroot/usr/lib >&5
i586-linux-gcc.br_real: error: unrecognized command line option '-R'; did you mean '-R'?

Fixes:
 - http://autobuild.buildroot.org/results/68623f22b49473177c889fe7b12625d779cbd1ed

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>