GrGLGpu: Fix typo in 'if' check
GrGLGpu: Fix typo in 'if' check

We were checking 'externalType' twice, and never checking
'internalFormat'.  We now check each of them once.

Change-Id: Iae0578a4828fd2a9224e4924245bea0708d8c931
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/227028
Reviewed-by: Brian Salomon <61fabaaf0876044aeedfd8e351e485c028d69e7b@google.com>
Commit-Queue: Brian Salomon <61fabaaf0876044aeedfd8e351e485c028d69e7b@google.com>

aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia