KVM: x86: selftests: svm_int_ctl_test: fix intercept calculation

INTERCEPT_x are bit positions, but the code was using the raw value of
INTERCEPT_VINTR (4) instead of BIT(INTERCEPT_VINTR).
This resulted in masking of bit 2 - that is, SMI instead of VINTR.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <49b9571d25588870db5380b0be1a41df4bbaaf93.1638486479.git.maciej.szmigiero@oracle.com>