bnxt_en: Remove unnecessary unsigned integer comparison and initialize variable

bnxt_en: Remove unnecessary unsigned integer comparison and initialize variable

There is no need to compare *val.vu32* with < 0 because
such variable is of type u32 (32 bits, unsigned), making it
impossible to hold a negative value. Fix this by removing
such comparison.

Also, initialize variable *max_val* to -1, just in case
it is not initialized to either BNXT_MSIX_VEC_MAX or
BNXT_MSIX_VEC_MIN_MAX before using it in a comparison
with val.vu32 at line 159:

	if (val.vu32 > max_val)

Addresses-Coverity-ID: 1473915 ("Unsigned compared against 0")
Addresses-Coverity-ID: 1473920 ("Uninitialized scalar variable")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>