Fix errant line contiuation syntax in chem code

[islas]

TYPE: bug fix

KEYWORDS: syntax

SOURCE: internal

DESCRIPTION OF CHANGES:
Problem:
There is invalid Fortran syntax for line continuation in the chem code. More sensitive compilers catch this as an error during the CMake build as files are not sanitized as much compared to the make build.

Solution:
Change the lines to be a single line.

ISSUE:
#2214

TESTS CONDUCTED:

1. Recreated issue noted in WRFCHEM fails to build with compile_new, KPP Enabled or standalone #2214 using Intel OneAPI compilers and testing code modifications to pass compilation successfully.

[weiwangncar]

The regression test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None