staging: r8188eu: Use sizeof dereferenced pointer in kzalloc()

staging: r8188eu: Use sizeof dereferenced pointer in kzalloc()

checkpatch.pl emits the following warning:

CHECK: Prefer kzalloc(sizeof(*pcmd)...) over kzalloc(sizeof(struct cmd_obj)...)
+       pcmd = kzalloc(sizeof(struct cmd_obj), GFP_KERNEL);

CHECK: Prefer kzalloc(sizeof(*psetkeyparm)...) over kzalloc(sizeof(struct setkey_parm)...)
+       psetkeyparm = kzalloc(sizeof(struct setkey_parm), GFP_KERNEL).

According to the above "CHECK[S]", use the preferred style in the two kzalloc()
of rtw_set_key().

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20220208180426.27455-2-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>